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Izmed vseh molekul, ki jih najdemo v živih organizmih, so proteini najbolj zastopani in s funkcionalnega stališča najbolj raznoliki. Sestavljeni so iz dolgih verig aminokislin in na njihovo konformacijo, strukturo ter stabilnost lahko vplivajo številni parametri. Vodne raztopine proteinov običajno vsebujejo soli, najbolj pogosto v obliki pufra. Poleg proteinov, soli in vode pa so v bioloških sistemih pogosto prisotne še druge makromolekule (lipidi, sladkorji, nukleinske kisline), in to v znatnih koncentracijah. Vpliv zasedenosti prostora s temi makromolekulami lahko v laboratorijskih razmerah ponazorimo z dodatkom nevtralnega polimera polietilen glikola. Soli in druge molekule tudi vplivajo na interakcije molekul proteina z raztopino. Eden izmed načinov ugotavljanja teh interakcij je merjenje zeta potenciala. To delo zajema meritve zeta potenciala v raztopinah proteina lizocima, kjer je bil prisoten tudi polietilenglikol v različnih koncentracijah (0, 100 in 150 g/l) in pri treh vrednostih pH (4,1, 7 in 9). Vedno je bil prisoten enostaven elektrolit (10 mM NaBr). Viskoznost raztopin polietilenglikola narašča z njegovo koncentracijo in tudi z dolžino polimerne verige. Z naraščajočo koncentracijo pa se zmanjšuje dielektrična konstanta raztopine. Rezultati kažejo, da zeta potencial narašča s koncentracijo polietilenglikola pri vseh treh izbranih pH vrednostih. Zeta potencial narašča tudi z dolžino polimerne verige. Poleg lizocima sem uporabila tudi protein goveji serumski albumin. Tudi pri tem proteinu se zeta potencial z naraščajočo koncentracijo polietilenglikola po absolutni vrednosti povečuje. Pri pH 7 je namreč naboj BSA negativen. Rezultati meritev zeta potenciala v sistemih brez polietilenglikola so primerljivi s tistimi v literaturi. Meritve v prisotnosti polietilenglikola pa še niso bile narejene. Proteins are the most abundant molecules found in living organisms, and, from a functional point of view, also the most diverse. They consist of long chains of amino acids and their conformation, structure and stability can be influenced by many parameters. Aqueous solutions of proteins usually contain salts, most often in the form of a buffer. In addition to proteins, salt, and water, other macromolecules (lipids, sugars, nucleic acids) are often present in biological systems. In laboratory conditions, influence of these macromolecules can be mimicked by the addition of the neutral polymer polyethylene glycol. Salts and other molecules affect the interaction between protein molecules. One way to determine these interactions is by measuring the zeta potential. In this work, I measured the zeta potential in lysozyme protein solutions, where polyethylene glycol was also present in different concentrations (0, 100 and 150 g/L) and at three pH values (4,1, 7 in 9). 10 mM NaBr salt was used in all cases. The viscosity of polyethylene glycol solutions increases with its concentration and also with the length of the polymer chain. As the concentration increases, the dielectric constant of the solution decreases. The results show that the zeta potential increases with polyethylene glycol concentration at all three pH values. The zeta potencial also increases with the length of the polymer chain. In addition to lysozyme, I also used the protein bovine serum albumin. For this protein, the zeta potencial increases in absolute value with increasing polyethylene glycol concentration. At pH 7, the charge of bovine serum albumin is negative. The results of zeta potential measurements in systems without polyethylene glycol are comparable to those in the literature. However, measurements in the presence of polyethylene glycol have not yet been made.

Uvod: Na področju ortotike, bolj natančno na področju ortopedskih vložkov, uporabljamo različne naravne kot tudi umetne materiale. Izbira materiala temelji na različnih mehanskih in površinskih lastnostih materiala, kot so: mejni kot, barva, hrapavost, trdota, natezna trdnost, zeta potencial in gostota. Izbira materiala je odvisna od potrebe pacienta. Namen: Določiti površinske in mehanske lastnosti penjenih in nepenjenih polimerov, ki se veliko uporabljajo v ortotiki in protetiki. Metode dela: Uporabili smo šest različnih materialov, natančno štiri penjene polimere: penjen polietilen, Poliform, Nora (EVA), prešano pluto in dva nepenjena polimera: polietilen in polipropilen. Vsem materialom smo določili mejni kot, barvne vrednosti, natezno trdnost, trdoto, zeta potencial in hrapavost. Z merjenjem mejnega kota na površini smo določili hidrofobnost oziroma hidrofilnost materialov. Pri barvnih vrednosti smo določili parametre CIE L*, a* in b*. Izmerili smo Youngov modul, natezno trdnost, raztezek in plastičnost materialov. Trdoto smo določili po metodi Shore A. Izmerili smo tudi topografije površin in določili Ra (aritmetično srednjo hrapavost) in Rq (kvadratična srednja hrapavost). Velikost zeta potenciala pa smo dobili z meritvijo pretočnega potenciala. Vsak material smo pomerili večkrat, nato pa smo izračunali povprečno vrednost ter standardni odklon. Rezultati: Najbolj hidrofoben material je zaprto celični PE. Poliform in penjen PE sta najbolj barvita materiala. Nora in pluta se po barvi približata barvi porjavele in rjave kože, medtem ko barva PE in PP ustreza barvi običajnega tipa kože. Poliform in penjen PE se ujemata s svetlejšo barvo kože. Natezna trdnost in trdota sta bile najvišje pri PE in PP. Največji negativni naboj je imel PE. Hrapavost pa je bila najbolj izrazita pri penjenem PE. Najmanjša hrapavost pa je bila pri PP. Razprava in zaključek: Ugotovili smo, da se penjeni in trdni materiali glede na mehanske lastnosti med seboj razlikujejo. Na splošno bi lahko rekli, da je izbrani PE v primerjavi z izbranim PP vzorcem trši, bolj hidrofoben, z višjo natezno trdnostjo, bolj negativno nabit in ima manjšo hrapavost. Med skupino penjenih polimerov pa je v veliki meri odstopal penjeni polietilen. Introduction: In the field of orthotics, more precisely in the field of orthopaedic insoles, we use various natural as well as artificial materials. The choice of material is based on different properties of the material, such as: the angle, colour, roughness, hardness, tensile strength, zeta potential and density. The choice of material depends on the needs of the patient. Purpose: Determine the superficial and mechanical properties of foamed and un-foamed polymers, which are widely used in the orthotics and prosthetics. Methods: We used six different materials, exactly four foamed polymers: foamed polyethylene, Poliform, Nora (EVA), a pressed cork and two unpadded polymers: polyethylene and polypropylene. All materials were defined as limit angle, colour values, tensile strength, hardness, zeta potential and roughness. By measuring the boundary angle on the surface, we determined the hydrophobicity or hydrophilicity of the materials. For colour values the CIE parameters L*, a* and b* were determined. Measured Young's modulus, tensile strength, elongation and plasticity of materials. Hardness was determined by methods Shore A. Surface topographies were also measured and Ra (arithmetic mean roughness) and Rq (square mean roughness) were determined. The magnitude of the zeta potential was measured by measuring the flow potential. Each material was calibrated several times, and then the mean value and standard deviation were calculated. Results: The most hydrophobic material is closed cell PE. Polyform and foam PE are the most colourful materials. Nora and cork approach the colour of tanned and brown skin, while the colour PE and PP correspond to the colour of the normal skin type. Polyform and PEfoam match the brighter colour of the skin. Tensile strength and hardness were highest in PE and PP. The biggest negative charge was PE. Roughness was most pronounced in PEfoam. However, the lowest roughness was in PP. Discussion and conclusion: We found that foam materials and solid materials differ from each other in terms of mechanical properties. In general, it could be said that the chosen PE is harder compared to the selected PP sample, more hydrophobic, with higher tensile strength, more negatively charged and has lowest roughness. Among the group of foamed polymers, however, PEfoam differed greatly.

Proteini so biološki linearni heteropolimeri, sestavljeni iz 20 različnih tipov monomerov, ki jih imenujemo aminokisline. So v naravi najbolj zastopane biološke makromolekule z zelo širokim naborom funkcij in obratovalnih okolij. Za funkcionalnost proteinov je ključna njihova tridimenzionalna struktura. Ta je odvisna od aminokislinskega zaporedja proteina in okolja, v katerem se protein nahaja. Pod določenimi pogoji lahko opazimo agregacijo proteinov, ki je večstopenjski proces pri katerem se proteini med seboj sprimejo. Na agregacijo pogosto gledamo kot na škodljiv proces, saj pri tem proteini izgubijo funkcionalnost, zato se raziskovalci trudijo razumeti mehanizme in vzroke proteinske agregacije. Z eksperimentalnimi tehnikami so prišli do dognanja, da v prvih stopnjah agregacije pride do interakcij med zaporedji, ki imajo navadno nenaključne deleže zastopanosti posameznih aminokislin. Ker pa so raziskave agregacije in vročih regij lahko zelo drage in zamudne, se vedno več ljudi želi študija agregacije lotiti s pomočjo metod molekulskega modeliranja in računske kemije. Kristalini so različni proteini, ki se v visokih koncentracijah nahajajo v očesnih lečah vretenčarjev. Zaradi specifike svojih nalog in dolge življenjske dobe so zelo dobro topni in stabilni, imajo pa tudi nenavadno visok lomni količnik. Posebni skupini med kristalini sta skupina β-kristalinov in skupina γ-kristalinov. Obe skupini imata zelo podobne strukture, glavna razlika pa je v tem, da so β-kristalini v obliki oligomerov, γ-kristaline pa najdemo strogo le v monomerni obliki. Leta 2021 je bila opravljena raziskava, kjer so z uporabo molekulske dinamike opazovali prve stopnje agregacije treh proteinov. Eden izmed njih je bil tudi človeški γD-kristalin. Cilj raziskave je bila detekcija vročih regij za agregacijo brez eksperimenta. Določene potencialne vroče regije so po sestavi zaporedij konzistentne z deleži, ki so bili določeni kot tipični za te regije z eksperimentalnimi metodami. V prvem delu naloge sem se s pomočjo Hartree-Fockove metode (HF metode) v programu Spartan'14 lotil računanja energije, ionizacijskega in elektrostatskega potenciala vročih regij v človeškem γD-kristalinu, z analizo dobljenih rezultatov pa sem poskusil prispevati nekaj k razumevanju agregacije tega proteina. V drugem delu naloge sem z eksperimentalnima tehnikama merjenja zeta potenciala in dinamičnega sipanja laserske svetlobe (DLS) poskusil opraviti nekaj raziskav oligomerne sestave govejega βL-kristalina v odvisnosti od koncentracije NaCl. Proteins are biological linear heteropolymers composed of 20 different types of monomers known as amino acids. Proteins are the most abundant biological macromolecules in nature with a very wide range of functions and operating environments. For functionality, a protein needs an appropriate structure. This depends on the amino acid sequence of the protein and the environment in which the protein is found. Under certain conditions, protein aggregation can be observed, which is a multi-step process in which proteins adhere to each other. Aggregation is often seen as a harmful process, as proteins lose their functionality in this process, so researchers are trying to understand the mechanisms and causes of protein aggregation. Using experimental techniques, they came to the interesting conclusion that in the first stages of aggregation, interactions occur between sequences that usually have non-random proportions of representation of individual amino acids. However, since the research of aggregation and hot regions can be very expensive and time-consuming, more and more people want to tackle the study of aggregation with the help of molecular modeling and computational chemistry methods. Various soluble proteins, which are found in high concentrations in the eye lenses of vertebrates, have been classified as crystallins. Due to the specificity of their tasks and their long lifespan, they are very soluble and stable, and they also have an unusually high refractive index. Special groups among crystallins are β-crystallins and γ-crystallins. Both groups have very similar structures, main difference being that β-crystallins are in the form of oligomers, while γ-crystallins are found strictly in monomeric form. In 2021, a study was carried out using molecular dynamics to observe the first stages of aggregation of three proteins, one of which was human γD-crystallin. The aim of the research was to detect hot regions for aggregations without an experiment. The composure of the identified potential hot regions was found to be consistent with the typical proportions of hot regions determined by experimental methods. In the first part of this assignment, with the help of Hartree-Fock method (HF method) in the Spartan'14 program, I determine the energy, ionization and electrostatic potential, of those hot regions in human γD-crystallin, and by analyzing the obtained results, I tried to contribute something to the understanding of the aggregation of this protein. In the second part of the assignment, I tried to do some research on the oligomeric composition of bovine βL-crystallin depending on the concentration of NaCl, using the experimental techniques of zeta potential and dynamic light scattering (DLS) measurements.

Skozi celotno obdobje rasti se mora koža sadja nenehno prilagajati povečanemu volumnu ploda in ima pomembno zaščitno funkcijo. Kožica je sestavljena iz primarne kože, povrhnjice in kožice oz. kutikule. Kutikula je zgornja hidrofobna plast, ki sadežu daje mehansko podporo in sadje varuje pred insekti, izgubo vode in ultravijoličnim sevanjem. Glavni cilj diplomske naloge je bil preučiti hrapavost, zeta potecial in mejni kot površine sadja. Pomembno vlogo imajo tudi kutikularni voski, ki ščitijo plod pred fizikalnimi (npr. sprememba temperatura, sevanje UV), kemičnimi (npr. fitofarmacevtska sredstva) in biološkimi spremembami (npr. mehanske poškodbe, insekti). Bakterije se na površino sadja lahko pritrdijo z adhezini, bički, fibrijami in zunajceličnimi polisaharidi. Pri pritrdljivosti bakterij pa imata pomembno vlogo hidrofobna celična površina in površinski naboj bakterij. Lastnosti površine sadja lahko določimo z mejnim kotom, zeta potencialom, mikroskopijo na atomsko silo ali vrstično elektronsko mikroskopijo. Pri mejnem kotu merimo kot, ki nastane med molekulami v kapljici in trdno površino pod njo. Pri tem velja, da večji kot je mejni kot, večja je hidrofobnost površine. Vsebnost voskov in trihomov na površini sadja je v povezavi z mejnim kotom, saj je zaradi hidrofobne narave le-teh mejni kot večji. Zeta potencial prikazuje površinski naboj delcev, odbojne koloidne sile med njimi in fizično stabilnost sistemov, pri čemer velja, da je koloidni sistem bolj stabilen pri večjem zeta potencialu. Za mikroskopijo na atomsko silo je značilna velika povečava z veliko ločljivostjo, kjer lahko pridobimo tudi slike 2D in 3D. Pri vrstični elektronski mikroskopiji gre za pridobivanje informacij s pomočjo vedenja elektronov in za ustvarjanje tridimenzionalnih slik o mikrostrukturi površine sadja. S pomočjo mikroskopije na atomsko silo in vrstične elektronske mikroskopije smo ugotovili, da se hrapavost sadja razlikuje glede na sorto in stadij zrelosti. Z vrstično elektronsko mikroskopijo smo ugotovili, da se bakterije redko pritrjujejo na gladko površino sadja in da jih pogosto najdemo v mikrorazpokah. Throughout the growing period, the fruit skin must constantly adapt to the increased volume of the fruit and it must maintain an important protective function. The cuticle consists of the primary skin, the epidermis and the dermis or cuticle. The cuticle is the top hydrophobic layer that provides mechanical support to the fruit and protects it from insects, water loss, and UV radiation. The main goal of this diploma thesis was to study the roughness, zeta potential and contact angle of the fruit surface. Cuticular waxes also play an important role in protecting the fruit from physical (temperature changes, UV radiation), chemical (pesticides), and biological changes (mechanical damage, insects). Bacteria can attach to the fruit surface through adhesins, flagella, fibrils and exopolysaccharides. However, the hydrophobic cell surface and the surface charge of bacteria play an important role in bacterial adhesiveness. Fruit surface properties can be determined by contact angle, zeta potential, atomic force microscopy, or scanning electron microscopy. The contact angle measures the angle formed between the molecules in the droplet and the solid surface beneath it. The higher the contact angle, the greater the hydrophobicity of the surface. The content of waxes and trichomes on the surface of the fruit is related to the contact angle, because of their hydrophobic nature, therefore contact angle is higher. Zeta potential shows the surface charge of the particles, the repulsive colloidal forces between them and the physical stability of the systems, with colloidal systems being more stable at higher zeta potentials. Atomic force microscopy (AFM) is characterized by high magnification with high resolution, where both 2D and 3D images can be obtained. Scanning electron microscopy (SEM) information is extracted from the behavior of electrons to produce three-dimensional images of the microstructure of the fruit surface. With microscopies AFM and SEM, we found that fruit roughness varies according to fruit species and stage of maturity. Using microscopy SEM, we also found that bacteria rarely attach to smooth fruit surface and are often found in microcracks.

V diplomskem delu sem opisala, kaj je zeta potencial, naštela njegove lastnosti in vplive, ki nanj delujejo. Z računi sem podala načine, s katerimi ga lahko izmerimo in posledično izračunamo, ter kje ga uporabljamo. Nato sem na splošno opisala kaj so mikoemulzije, podala njihove lastnosti in v čem se razlikujejo od emulzij. Naštela sem tudi njihove prednosti in slabosti, opisala njihovo uporabo, ter opisala kako se zeta potencial uporablja za določevanje stabilnosti v farmacevtski industriji. In my bachelor’s thesis, I explained what zeta potential is, described its properties and explained the factors that can have an impact on it. With equations I described methods of how we can measure and calculate zeta potential and added uses of zeta potential. Furthermore, I described the meaning and properties of microemulsions and described differences with emulsions. Moreover, I described their advantages and disadvantages and explained their use and how zeta potential is used to describe the stability of microemulsions in the field of pharmacy.

Mezenhimske matične celice predstavljajo heterogeno skupino celic, ki jih lahko izoliramo iz številnih tkiv odraslega človeka. Zanimive so predvsem zaradi njihove sposobnosti migracije na mesto vnetja v telesu, kjer izločajo različne topne dejavnike kot so citokini, kemokini in rastni dejavniki, ki izboljšujejo angiogenezo, zavirajo vnetje in inhibirajo apoptozo. Zaradi številnih imunomodulatornih in regenerativnih lastnosti je vedno več zanimanja za uporabo mezenhimskih matičnih celic v kliniki pri številnih patoloških stanjih, za katere sta značilna vnetje in degeneracija tkiva. Vse večji obseg uporabe zahteva tudi vse boljše tehnike ločevanja celic, ki morajo biti hitrejše in bolj učinkovite. Namen naloge je bil raziskati potencialne materiale, ki bi bili ustrezni za ločevanje mezenhimskih matičnih celic od ostalih celic. V raziskovalni nalogi smo uporabili humane mezenhimske matične celice, izolirane iz kostnega mozga. Najprej smo okarakterizirali vzorce materialov z izbranimi tehnikami, in sicer smo merili zeta potencial, kontaktni kot ter hrapavost. V nadaljevanju smo ugotavljali vpliv lastnosti materialov na obnašanje celic – na njihovo adhezijo. Za najbolj učinkovit material se je izkazala mikrotitrska plošča s fibronektinom, na katero se je vezalo največ mezenhimskih matičnih celic. Na ostalih materialih nismo dobili ponovljivih rezultatov, zato nismo prišli do jasnih zaključkov. Ugotovili smo, da so interakcije med celicami in materiali zelo kompleksne in da je za njihovo razumevanje potrebno še precej raziskav. Iskanje novih metod ločevanja celic je težavno, saj je nemogoče določiti enostaven kriterij za uspešno adhezijo in nato ločevanje celic. Mesenchymal stem cells represent a heterogeneous group of cells that can be isolated from several adult tissues. In recent years the main interest is in their ability to migrate to the site of inflammation in the body, where they secrete various soluble factors such as cytokines, chemokines, and growth factors that improve angiogenesis, inhibit inflammation, and inhibit apoptosis. Their immunomodulatory and regenerative properties are the reason for increasing interest for clinical applications, where they could be used for treatment of many pathological conditions related to inflammation and tissue degeneration. Increasing use requires better cell separation techniques, which need to be faster and more efficient. The purpose of our research was to investigate potential materials which would be suitable for mesenchymal stem cell separation from other cells. We used bone marrow derived human mesenchymal stem. In the first part of the research, we characterized sample materials via measuring the zeta potential, contact angle and roughness. In the second part, we determined the influence of the material properties on the behavior of cells - on their adhesion. The best results were shown on the fibronectin coated microtiter plate, as the largest proportion of mesenchymal stem cells adhered to this material. We did not get consistent results on the other materials, therefore we did not come to clear conclusions. We have confirmed that cell-material interactions are very complex and still need to be researched in detail. Finding new methods for cell separation is difficult, as it is impossible to determine simple criteria for successful adhesion and following cell separation.

V okviru diplomskega dela sem raziskovala vpliv oplaščenja magnetnih nanodelcev na zeta potencial in njihove magnetne lastnosti. Delce smo sintetizirali v laboratoriju iz dveh raztopin soli, nato pa jih oplaščili s citronsko kislino in cetiltrimetilamonijevim bromidom. Fokus moje raziskave je bil posvečen funkcializaciji in karakterizaciji oplaščenih magnetnih delcev za namene polifenolne ekstrakcije iz lesne biomase. Nanodelci so morali imeti točno določeno koncentracijo in izražati superparamagnetne lastnosti za njihovo nadaljnjo uporabo. Tako bi lahko na ekološko prijazen način iz lesne biomase ekstrahirali polifenole in izboljšali uporabo lesnega odpadka. Ugotovili smo, da vsi nanodelci izražajo superparmagnetne lastnosti, kot boljši surfaktant pa se je izkazala citronska kislina, saj so bile izmerjene vrednosti zeta potenciala višje, prav tako pa je oplaščenje znižalo izoelektrično točko, s tem pa je postala suspenzija bolj stabilna pri fizioloških pogojih As part of my bachelor thesis, I investigated the influence of the coating of magnetic nanoparticles on the zeta potential. The particles were synthesized from two salt solutions and then coated with citric acid or cetyltrimethylammonium bromide. Our research was focused on the functionalization and characterization of coated magnetic particles for polyphenolic extraction from wood biomass. The nanoparticles had to have a specific concentration and express superparamagnetic properties for their further use. In this way, polyphenols could be extracted from wood biomass in an environmentally friendly way, thus improving the use of wood waste. We found that all nanoparticles exhibit superparamagnetic properties, and citric acid proved to be a more suitable surfactant, as the measured zeta potential values were higher than in the sample coated with CTAB. The citric acid coating also lowered the isoelectric point, making the suspension more stable at the desired conditions.

Z ionsko izmenjevalno kromatografijo sem v raztopini poli(alilamin hidroklorida) kloridne ione zamenjal s hidroksidnimi in tako pripravil rahlo bazično raztopino polialilamina. Vzorce merjenih raztopin polialilaminskih soli sem pripravil z dodajanjem izbrane količine raztopin različnih kislin v založno raztopino polialilamina. Tako pripravljenim raztopinam izbranih soli (F-, Cl-, Br-, I-, ClO4-, NO3-, AcO-, CF3COO-, C6H13COO- in PhSO-) polialilamina z različnimi stopnjami nevtralizacije (od 0 % do 120 %) sem pri 20 °C oziroma 25 °C izmeril viskoznost, viskozni in elastični modul ter določil zeta potencial in hidrodinamski radij. Preučeval sem odvisnost teh lastnosti od vrste protiionov, koncentracije polielektrolita, molekulske mase polielektrolita in stopnje nevtralizacije. V delu skušam pojasniti vpliv ionov na izmerjene lastnosti raztopin. With ion exchange chromatography I substituted the chloride ions in a solution of poly(allylamine hydrochloride) with hydroxide ions, obtaining a mildly basic solution of polyallylamine. I prepared measuring solutions of polyallylamine salts by adding different acid solutions to the batch solution of polyallylamine. The aqueous solutions of chosen polyallylamine salts (F-, Cl-, Br-, I-, ClO4-, NO3-, AcO-, CF3COO-, C6H13COO- in PhSO3-) with different degree of neutralization (from 0 % to 120 %) were characterized by measuring viscosity, elastic and viscous modulus as well as zeta potential together with hydrodinamic radious. I studied the effect of counterion type, polyelectrolyte concentration, polyelectrolyte molecular mass and the degree of neutralization on solution properties. In my thesis I explain the impact different ions have on the solution.

Uvod: Ortoze so rigidni, polrigidni ali mehki pripomočki, pritrjeni na del telesa. Pod rigidnim delom ortoze je nameščen tekstilni material, zaradi katerega je nošenje ortoze bolj udobno. Ti materiali so mehki in so v stalnem stiku s kožo, zato je mogoča adhezija bakterij iz kožne mikrobiote. Človeška koža je gosto naseljena z mikroorganizmi, ki predstavljajo našo mikrobioto. Adhezija bakterij na površine materialov je pogojena s številnimi dejavniki, kot so zeta potencial, hrapavost in hidrofobnost materiala. Prav tako na adhezijo vplivajo karakteristike bakterij. Namen: Ugotoviti, koliko in kakšne bakterije se nahajajo v naravni mikrobioti kože. Ugotoviti, kako zeta potencial materialov in njihova hidrofobnost vplivajo na adhezijo bakterij, ki se nahajajo na površini kože. Rezultate med seboj primerjati in ugotoviti, ali je kateri izmed petih materialov bolj odporen proti adheziji bakterij. Rezultate primerjati z ugotovitvami v drugi strokovni literaturi. Metode dela: V diplomskem delu smo uporabili pet materialov, ki se uporabljajo pri izdelavi ortoz: Neopren, Najlon, Lycra, xDRY in bambusova vlakna. Pri teh materialih smo izmerili zeta potencial, določili mejni kot in s tem ugotovili njihovo hidrofobnost. V treh poskusih smo materiale nalepili na tri različna mesta na koži. Na teh mestih smo odvzeli tudi mokri bris. Materiale smo pustili nalepljene 12 ur in jih nato za 30 sekund odtisnili v krvni agar. Vzorce smo inkubirali 24 ur pri 37 °C ter nato prešteli kolonije bakterij. Rezultati: Največji zeta potencial smo izmerili na bambusovih vlaknih, nekoliko manjši zeta potencial sta imela Najlon in Lycra, najbolj negativen potencial pa xDRY in Neopren. Neopren in xDRY sta hidrofobna materiala, pri slednjem je bil izmerjen nekoliko večji mejni kot. Za ostale materiale pa smo določili, kako hitro vpijejo kapljico vode. Bambusova vlakna so najbolj hidrofilen material, sledita Najlon in Lycra. Število adheziranih bakterij je bilo od 0 do 2 koloniji na posameznem nanosu. Razprava in sklep: Na vse materiale se je v povprečju adhezirala manj kot ena kolonija bakterij. Najmanj adheziranih bakterij je bilo na Neoprenu, ki je imel tudi najbolj negativen zeta potencial. Največje število bakterij pa se je adheziralo na Najlon. V primerjavi s številom kolonij pri mokrem brisu pa je število kolonij na vseh materialih ostalo nizko. Iz dobljenih rezultatov lahko sklepamo, da so materiali primerni za uporabo v ortotiki. Introduction: Orthoses are rigid, semi-rigid or soft devices, attached to external part of the body. Under the rigid part of orthoses there is a textile material, which makes wearing of the orthosis more comfortable. These materials are in constant contact with the skin, that makes them more exposed for bacterial adhesion from skin microbiota. Microorganisms that inhabit human skin represent our natural microbiota. Bacterial adhesion to the surfaces of materials is conditioned by a number of factors such as: zeta potencial, roughness and hydrophobicity of the material and is also affected by the characteristics of the bacterias. Purpose: Determine how many and what kind of bacterias are found in the natural skin microbiota. To determine how zeta potencial and hydrophobicity of the materials affect adhesion of bacterial from the surface of the skin. Comparing results and decide which of five materials is more resistant to bacterial adhesion and compare those results with other literature. Methods: Five different materials that are used in production of orthoses, were used for the research: Neoprene, Nylon, Lycra, xDRY and Bamboo Fibers. We measured zeta potencial and determined hydrophobcitiy for these materials, which were then attached to three different places on the skin within three different experiments. On the same places we also took a wet swab. Materials were attached for 12 hours and then imprinted in blood agar for 30 seconds. The samples were incubated for 24 hours at 37°C, after that bacterial colonies were counted.Results: The highest zeta potencial was on Bamboo fibers, followed by Nylon, Lycra, xDRY and the lowest potencial was measured on Neoprene. Neoprene and xDRY are hydrophobic materials, where xDRY has a higher contact angle. Other three materials are hydrophilic, so we determined how quckly the materials are absorbing a drop of water. The most hydrophilic materials is Bamboo fiber, next is Nylon and the least hydrophilic is Lycra. The avarage number of adhered bacterias ranged from 0 to 2 colonies per application Discussion and conclusion: On average, less than one colony of bacteria adhered to every material. The number of adhered bacterias was the lowest on Neopren, which also had the most negative zeta potencial. And the largest number of adheres bacterias was on Nylon. However the number of colonies on all materials remained low in comparison with the number of colonies on wet swabs. From the obtained results we can conclude that the materials are sutable for use in orthotics.

Uvod: V ortotiki in protetiki se uporabljajo različni naravni in umetni materiali. Izbira materiala je odvisna od potreb pacienta. Kožo kolonizirajo različni mikroorganizmi, eden izmed njih je Staphylococcus aureus. Na adhezijo bakterij vplivajo dejavniki okolja ter hidrofobnost, hrapavost in površinski naboj. Namen: Določiti adhezijo bakterije Staphylococcus aureus na izbranih površinah, preveriti učinkovitost vsebnosti srebrovih nanodelcev in ugotoviti, kako na vse skupaj vplivajo hrapavost, zeta potencial in mejni kot površin. Metode dela: Uporabili smo osem različnih materialov: etilen vinil acetat, etilen vinil acetat s srebrovimi nanodelci, zaprto-celično polietilensko peno, zaprto-celično polietilensko peno s srebrovimi nanodelci, naravno pluto, termo-pluto, naravno usnje in umetno usnje. Izmerili smo hrapavost, mejni kot in zeta potencial površin. V raziskavi smo uporabili sev bakterije Staphylococcus aureus, izoliran iz človeka. Materiale smo sterilizirali pod UV svetlobo in jih inkubirali s kulturo izbrane bakterije. Osušene površine smo opazovali pod vrstičnim elektronskim mikroskopom ter s posnetkov določili število bakterij na površino. Rezultati: Največjo hrapavost smo izmerili na zaprto-celični polietilenski peni, najmanjšo pa na površinah etilen vinil acetata. Največji negativni naboj ima umetno usnje. Termo-pluta ima najmanjši negativni naboj. Zaprto-celična polietilenska pena s srebrovimi nanodelci je najbolj hidrofoben material, medtem ko ima umetno usnje najmanjši mejni kot. Največ bakterij na kvadratni milimeter površine smo izmerili na zaprto-celični polietilenski peni s srebrovimi nanodelci, najmanj pa na etilen vinil acetatu. Razprava in zaključek: Največji vpliv na adhezijo bakterij ima hrapavost, sledi ji mejni kot. Naravni materiali so manj dovzetni za adhezijo bakterij kot umetni. Površine z vsebnostjo srebrovih nanodelcev se niso izkazale za najbolj bakteriostatične, zato bi bilo to področje potrebno dodatno raziskati. Introduction: In orthotics and prosthetics different natural and synthetic materials are used. The choice of material depends on the needs of the patient. The skin is colonized by different microorganisms, one of which is Staphylococcus aureus. Bacterial adhesion is influenced by environmental factors and also by hydrophobicity, surface roughness and surface charge. Purpose: To determine adhesion of Staphylococcus aureus on selected surface areas, to check the effectivness of silver nanoparticle content and find out how all of this is affected by roughness, zeta potential and contact angle. Methods: We used eight different materials: ethylene-vinyl acetate, ethylene-vinyl acetate with silver nanoparticles, closed-cell polyethylene foam, closed-cell polyethylene foam with silver nanoparticles, natural cork, thermo-cork, natural leather and synthetic leather. We measured the roughness, contact angle and zeta potential of surfaces. In research we used a strain of Staphylococcus aureus bacteria, isolated from human. Materials were sterilized using UV light and incubated with a chosen bacterial culture. We observed dried surfaces using a scanning electron microscope and determined the number of bacteria per unit surface area, using microscope images. Results: The highest roughness was measured on closed-cell polyethylene foam, while ethylene-vinyl acetate had the lowest one. The largest negative charge was measured on synthetic leather. Thermo-cork had the lowest negative charge. Clossed-cell polyethylene foam with silver nanoparticles is the most hydrophobic of used materials, while synthetic leather had the lowest contact angle. The largest number of bacteria per square milimeter was found on closed-cell polyethylene foam with silver nanoparticles and the lowest on ethylene-vinyl acetate. Discussion and conclusion: The adhesion of bacteria is most significantly influenced by surface roughness, followed by contact angle. Natural materials are less susceptible to bacterial adhesion compared to the synthetic ones. Surface areas with silver nanoparticle content were found not to be the most bacteriostatic and thus, for this reason, this subject matter requires additional research.

Onesnaževanje okolja s težkimi kovinami in reševanje le te problematike na učinkovit in hkrati ekonomsko sprejemljiv način, predstavlja vedno večji izziv v današnjem času. V diplomski nalogi smo preučevali adsorpcijske lastnosti bentonita za adsorpcijo kovinskih ionov (železo, baker, svinec) iz vodne raztopine. Masne koncentracije kovinskih ionov v raztopini smo določili z optično emisijsko spektroskopijo (ICP OES). Prav tako smo preučili karakteristike samega bentonita (velikost delcev, zeta potencial, specifična površina, volumen por). Karakterizacija je pokazala, da je v našem vzorcu bentonita povprečni zeta potencial - 0,257 mV in povprečna velikost delcev 1657 nm. Ugotovili smo, da s spreminjanjem pH raztopin Fe2+, Cu2+ in Pb2+ ionov, bentonit najbolje adsorbira pri pH vrednosti 7. Spreminjali smo tudi koncentracije samih raztopin z Fe2+, Cu2+ in Pb2+ ionov v območju od 1 mM do 13 mM in izmerili, da ima bentonit največjo kapaciteto pri koncentraciji 13 mM. Prav tako smo preizkusili medsebojni vpliv ionov na adsorpcijo in ugotovili, da je učinkovitost adsorpcije vseh treh ionov nad 99 %. Iz rezultatov diplomskega dela lahko sklepamo, da je bentonit odlična izbira za odstranjevanje železovih, bakrovih in svinčevih ionov iz vode. Heavy metal pollution and how to solve this problem in an efficient and economically acceptable way, represents one of the biggest problems in our modern world. In diploma thesis, we examined adsorption capacity of bentonite for the adsorption of metal ions (iron, copper, lead) from aqueous solution. The mass concentrations of the metal ions in the solution has been determinated by optical emission spectroscopy (ICP OES). Furthermore, the characteristics of bentonite (particle size, zeta potential, specific surface area, pore volume) has been examined. Characterization showed that for our sample of bentonite, the average zeta potential was 0.257 mV and the average particle size was 1657 nm. We observed that by changing the pH of Fe2+, Cu2+ and Pb2+ ion solutions, bentonite absorbs best at pH value of 7. By varying the concentration of the solutions of Fe2+, Cu2+ and Pb2+ ions in range from 1 mM to 13 mM it was found that bentonite has the highest capacity at a concentration of 13 mM. In addition, we investigated the interactions of the ions in solution and their influence on adsorption and we realised that the adsorption efficiency of all three ions was above 99 %. The results of the thesis lead to the conclusion, that bentonite is an excellent choice for the removal of iron, copper and lead ions from water.

Diplomsko delo je rezultat preučevanja adsorpcije težkih ionov Pb2+, Cu2+ in Fe2+ na zeolit. Ker so ti ioni zelo močni onesnaževalci okolja, se pojavlja vprašanje kako zaščititi naravo pred njihovimi škodljivimi vplivi. Ena iz med možnosti je adsorpcija ionov na močen adsorbent, kar je v našem primeru zeolit. Tako je bistveno, da dobro spoznamo zeolit, preučimo njegovo strukturo in lastnosti, ter nato z različnimi kemijskimi analizami določimo, kakšne zmožnosti adsorpcije ima zeolit. Namen diplomske naloge je bil določiti adsorpcijske lastnosti zeolita v raztopini za adsorpcijo ionov težkih kovin ( Cu2+, Fe2+, Pb2+ ), določiti masne koncentracije kovinskih ionov z optično emisijsko spektroskopijo (ICP OES), ter preučiti specifiko samega zeolita (zeta potencial, specifična površina, velikost delcev). Za ugotavljanje adsopcijskih lastnosti zeolita smo spreminjali dva ključna parametra, koncentracijo raztopine težkih ionov, ter pH raztopine. S spreminjanjem teh parametrov smo prišli do ugotovitve, da so najbolj optimalni pogoji za adsorpcijo pri koncentraciji 13 mM in pri pH vrednosti 7. S preiskovanjem vpliva koncentracije težkih ionov na adsorbent smo ugotovili, da uspešnost adsorpcije pri višji koncentraciji upada, izjema je le baker. Pri spreminjanju pH vrednosti, pa se je izkazalo, da pH nima takšen velik vpliv na adsorpcijo kot jo ima koncentracija, saj smo ugotovili, da se adsorpcijska sposobnost malo zmanjša le pri zelo nizki pH vrednosti ( pH = 2,5 ). Ugotavljali smo tudi medsebojni vpliv ionov na učinkovitost adsorpcije ionov na zeolit, pri čemer se je izkazalo, da mešanica ionov v raztopini dobro vpliva na adsorpcijo, saj je bila v našem primeru učinkovitost adsorpcije za vse tri ione nad 99%. The diploma thesis is the result of studying the adsorption of heavy metal ions of Pb2+, Cu2+ and Fe2+ on zeolite. Since this ions are very powerful pollutants of the environment, the question arises as how to protect nature from their harmful effects. One of the possibilities is the adsorption of ions on a strong adsorbent, which in our case is zeolite. It is essential to get to know the zeolite well, to study its structure and properties, and then to determine, through various chemical analyzes, what is the zeolite's adsorption capacity. The purpose of this thesis was to determine the adsorption properties of zeolit for adsorption of heavy metal ions (Cu2+, Fe2+, Pb2+) in solution, to determine the mass concentrations of metal ions by optical emission spectroscopy (ICP OES), and to study the specificity of the zeolite itself (zeta potential, specific surface area, particle size). In order to determine the adsorption properties of zeolite, two key parameters, the concentration of the heavy metal ions in solution and the pH of the solution, have been studied. By changing these parameters, the most optimal conditions for adsorption were determined at a concentration of 13 mM and at a pH value of 7. By examining the influence of the concentration of heavy metal ions on the adsorbent, we found that the adsorption efficiency at a higher concentration decreases, with the exception of copper. When changing the pH value, it turned out that pH did not have as much effect on adsorption as the concentration, since we found that the adsorption efficiency decreased only at very low pH (pH = 2.5). We also investigated the interaction of ions on the adsorption efficiency of the zeolite, which showed that the mixture of ions in solution had a good effect on adsorption, since in our case the adsorption efficiency for all three ions was above 99%.

Onesnaževanje z odpadnimi vodami predstavlja velik delež onesnaževanja narave. V teh odpadnih vodah se pogosto nahajajo tudi težke kovine, ki jih moramo zaradi ogrožanja okolja, živali in ljudi iz vode odstraniti. Kot poceni metoda za odstranjevanje težkih kovin iz vode, se je uveljavila adsorpcija. V iskanju učinkovitih ter poceni adsorbentov, se je dobro izkazala tudi žlindra, ki je stranski produkt pri proizvodnji jekla. V diplomskem delu predstavljamo rezultate raziskave adsorpcijskih lastnosti bele žlindre. Žlindri smo najprej določili specifično površino BET, volumen por, premer por, velikost delcev in zeta potencial. Nadalje smo preučevali vpliv pH in koncentracije na adsorpcijo železovih, bakrovih in svinčevih ionov. Hkrati smo preučili še medsebojni vpliv izbranih ionov na adsorpcijo. Preučevali smo učinkovitost in kapaciteto adsorpcije in iz rezultatov ugotovili, da pH minimalno vpliva na adsorpcijo bakra in železa, svinec pa ima adsorpcijski maksimum pri pH 7. Pri preiskovanju vpliva koncentracije smo ugotovili, da učinkovitost adsorpcije s koncentracijo narašča za svinec, na baker in železo pa skoraj ne vpliva, saj je bila učinkovitost v območju koncentracij od 1 mM do 13 mM 100 %. Medsebojni vpliv ionov daje pozitivne rezultate na učinek adsorpcije. Waste water pollution represents a substantial share in environmental pollution. Quite often, waste waters contain heavy metals – and because they pose a threat to the environment, animals and humans, their removal from water is necessary. Adsorption has become a widely used and inexpensive method for removing heavy metals from water. In search for efficient and inexpensive adsorbents, slag, a steel-making by-product, has performed rather well. The present diploma thesis presents the findings of the study of white slag adsorption properties. First, specific surface area BET of slag was determined as well as pore volume, pore diameter, particle size and zeta potential. The next step was the determination of how pH and concentration affect the adsorption of iron, copper and lead ions. The interaction of the selected ions and their impact on the adsorption process was also studied. The results of adsorption efficiency and capacity reveal that the pH has minimal effect on the adsorption of copper and iron for lead the adsorption maximum is at pH 7. Higher concentrations resulted in better adsorption efficiency for lead but hardly affected the adsorption of copper and iron – the efficiency range being from 1 mM to 13 mM 100%. The interaction of ions positively affects the adsorption efficiency.

Delci nanometrskih velikosti z lipidnim dvoslojem, katerim krajše pravimo kar vezikli, so zadnja leta predmet raziskovanj mnogih znanstvenikov, saj so potencialno uporabni za diagnosticiranje in zdravljenje različnih bolezni. Vezikli nastajajo v naravi, lahko pa jih ustvarimo tudi sami. V magistrskem delu smo se ukvarjali z vezikli, ki smo jih pripravili sami, iz koncentriranega jajčnega lecitina, s postopkom imenovan ekstrudiranje. Zanimalo nas je predvsem, kakšen vpliv ima dodajanje različnih surfaktantov na velikost in zeta potencial pripravljenih veziklov. Velikost smo ocenili z merjenjem hidrodinamskega radija. Spreminjanje velikosti hidrodinamskega radija smo spremljali preko dinamičnega sipanja svetlobe, velikosti zeta potenciala pa preko elektrokinetičnih meritev. V suspenzijo smo dodajali tri surfaktante: kationski - dodecil piridinijev klorid (DPC), anionski - natrijev dodecil sulfat (SDS) in neionski - Brij 30. Prav tako smo spremljali vpliv dodatka sladkorja (trehaloze) in temperature na stabilnost veziklov. Vse eksperimente in meritve smo opravljali pod enakimi pogoji, da bi zagotovili čim boljšo primerjavo med rezultati. Dodajanje kationskega surfaktanta DPC je povzročilo povečanje veziklov pri nižjih koncentracijah surfaktanta, ter razgradnjo pri višjih koncentracijah surfaktanta. Zeta potencial pa se je bolj približal pozitivnim vrednostim. Višanje temperature pa ni imelo opaznega vpliva niti na velikost radija niti na zeta potencial veziklov. Dodajanje anionskega surfaktanta SDS je pokazalo nenavadne rezultate, predvsem glede velikosti radija veziklov, saj je večinoma do sprememb prišlo pri vzorcih, ki so vsebovali trehalozo, torej le-ta ni poskrbela za zaščito veziklov. Zeta potencial pa je postal še bolj negativen, vendar pa se s temperaturo ni bistveno spreminjal. Dodajanje neionskega surfaktanta Brij 30 je prav tako povzročilo spreminjanje velikosti veziklov. Pri višjih koncentracijah surfaktanta in višji koncentraciji trehaloze je prišlo do razgradnje veziklov, pri nižjih dodatkih in manjši koncentraciji trehaloze pa do vgradnje surfaktanta v vezikle. Rezultati meritev zeta potenciala pa so pričakovano ostali podobni prvotnim vrednostim. Nanometer-sized particles with lipid double layer, named vesicles, are lately being investigated by many scientists because of their potential in diagnostic and treatment of different diseases. Vesicles are made naturally, but they can be produced in a laboratory as well. In this master's thesis, we were researching vesicles which we made from egg's lecithin concentrate with a process called extrusion. We wanted to know the effect on the size and the zeta potential of vesicles after adding different surfactants. The size was evaluated by measuring the hydrodynamic radius. We were following the changes in the size of the hydrodynamic radius through dynamic light scattering and the changes in the size of zeta potential through electrophoretic measurements. In suspension, we added three surfactants: cationic - dodecyl pyridinium chloride (DPC), anionic - sodium dodecyl sulfate (SDS)) and non-ionic - Brij 30. We were also following the effect of added sugar (trehalose) and temperature on vesicle stability. All the experiments and measurements were made under the same conditions to ensure the optimal comparison between results. Adding cationic surfactant DPC caused bigger vesicles at lower concentrations of surfactants and degradation at higher concentrations of surfactants. Zeta potential came closer to positive values. Rising the temperature did not have any significant effect on the size of the radius and the zeta potencial of vesicles. Adding of the anionic surfactant SDS gave a little less expected results, mostly about the size of the vesicle's radius, because the most changes happened with samples which have had trehalose in it, so it did not protect the vesicles. Zeta potential became more negative, and it did not change a lot with temperature. Adding neutral surfactant Brij 30 also made changes in the size of vesicles. At higher concentration of surfactant and higher concentration of trehalose the vesicles degraded, at lower concentration and at lower concentration of trehalose the surfactant incorporated into vesicle's bilayer. Results of zeta potential stayed similar to original values, as expected.

Uvod: Ključen sestavni del proteze je ležišče. Ležišče je v neposrednem stiku s kožo krna, kar daje možnost za prenos bakterij iz kože na material. Najbolj razširjena vrsta bakterij stalne mikrobiote kože so stafilokoki, med katere spada bakterija Staphylococcus epidermidis. Na adhezijo bakterij na površino vplivajo različni dejavniki, kot so hrapavost, zeta potencial površine in hidrofobnost površine materiala. Namen: Ugotoviti kako hrapavost površine, zeta potencial površine, hidrofobnost površine materiala in specifične interakcije vplivajo na stopnjo adhezije bakterije Staphylococcus epidermidis na materiale, ki so v stiku s krnom in jih med seboj primerjati. Metode dela: Za raziskavo smo uporabili štiri različne materiale, ki se uporabljajo za izdelavo ležišč in vložkov za krn: akrilno smolo, mešanico etilen-vinil acetata in polietilena nizke gostote, silikon in termoplastični elastomer. Tem materialom smo izmerili hrapavost površine, mejni kot za določitev hidrofobnosti in zeta potencial površine. Za raziskavo smo uporabili standardni sev bakterije Staphylococcus epidermidis in ji določili rastno krivuljo. Za določitev stopnje adhezije bakterij na materiale smo kulturo bakterije Staphylococcus epidermidis inkubirali s sterilnimi preučevanimi materiali. Površine smo nato fiksirali in posušili. Z vrstičnim elektronskim mikroskopom smo naredili posnetke površin in prešteli bakterije na posnetkih in izračunali delež pokritosti opazovane površine z bakterijami. Rezultati: Največjo hidrofobnost smo zmerili na silikonu, nekaj manjšo na akrilni smoli, še manjšo na termoplastičnem elastomeru in najmanjšo na materialu mešanice etilen-vinil acetata in polietilena nizke gostote. Hrapavost je bila največja na termoplastičnem elastomeru, nekaj manjša na mešanici etilen-vinil acetata in polietilena nizke gostote, še manjša na silikonu in najmanjša na akrilni smoli. Najbolj negativni zeta potencial smo izmerili na silikonu, najmanj negativni pa na mešanici etilen-vinil acetata in polietilena nizke gostote. Površina termoplastičnega elastomera ni bila izmerjena. Stopnja adhezije je bila največja na termoplastičnen elastomeru, nekaj manjša na silikonu, vidno manjša na mešanici etilen-vinil acetata in polietilena nizke gostote in najmanjša na akrilni smoli Razprava in sklep: Dejavnik, ki najbolj vplival na stopnjo adhezije je hrapavost površine na termoplastičnem elastomeru in akrilni smoli. Sklepamo, da je velika stopnja adhezije na silikonu posledica visoke hidrofobnosti materiala in relativno majhna stopnja adhezije na mešanici etilen-vinil acetata in polietilena nizke gostote posledica vsebnosti srebrovih ionov. Introduction: The key component of the prosthesis is the socket. The socket is in direct contact with the skin of the stump, which gives an option for bacteria to transfer from skin to material surface. The most common type of bacteria in permanent microbiota of the skin are staphylococci, among which is the bacterium Staphylococcus epidermidis. The adhesion of bacteria to the surface is influenced by various factors, such as roughness, surface charge and hydrophobicity of the material surface. Purpose: To determine how roughness, surface charge and hydrophobicity of the material surface influence the degree of adhesion of Staphylococcus epidermidis to materials that are in contact with the stump and compare them with each other. Methods: Four different materials used for the production of sockets and liners were used for the research: acrylic resin, mixture of ethylene-vinyl acetate and low-density polyethylene, silicone and thermoplastic elastomer. We measured surface roughness of the material surface, contact angle for determining the hydrophobicity of the surface and zeta potential to determine surface charge. For the research we used the standard bacteria Staphylococcus epidermidis and determined growth curve of the bacteria. To determine the adhesion of the bacteria to the materials, the sterile materials were immersed in the culture medium of the Staphylococcus epidermidis bacterium and were incubated for 10 hours. The surfaces were then fixed and dried. Through scanning electron microscope we produced surface images, counted bacteria on the image and calculated proportion of bacteria coverage on the surface. Results: The highest hydrophobicity was measured on silicone, followed by acrylic resin, thermoplastic elastomer and mixture of ethylene-vinyl acetate and low-density polyethylene. The roughness was the highest on thermoplastic elastomer followed by mixture of ethylene-vinyl acetate and low-density polyethylene, silicone and least on acrylic resin. The smallest zeta potential was measured on mixture of ethylene-vinyl acetate and low-density polyethylene, folowed by acrylic resin, and silicone. Thermoplastic elastomer was not measured. Adhesion was the highest in thermoplastic elastomer and silicone respectively, and visibly less on mixture of ethylene-vinyl acetate and low-density polyethylene and least on acrylic resin. Discussion and conclusion: The results showed that roughness of the surface had the greatest effect on adhesion on thermoplastic elastomer and acrylic resin. High adhesion on silicone can be attributed to the high hydrophobicity of the material. Relatively small adhesion on mixture of ethylene-vinyl acetate and low-density polyethylene could be the result of the content of silver ions.

Silikoni so široko uporabni materiali. Med številnimi aplikacijami jih najdemo tudi kot sestavni del timpanalnih cevk, kjer je cilj napredek razvoja funkcionalnih površin cevk na način, ki izboljša procese zdravljenja vnetja ušes ter druga stanja ušesnih bolezni, kjer se uporabljajo te cevke. V magistrski nalogi smo se osredotočili na pripravo silikonskih površin z različnimi protimikrobnimi premazi. V našem primeru smo naredili premaze iz nanodelcev, kjer smo dodali amoksiklav, ali pa so bili nanodelci samo iz tripolifosfata in hitozana, katera lahko spontano tvorita nanodelce. Velikost delcev smo izmerili z metodo DLS, stabilnost disperzije smo preverili z meritvami Zeta potenciala, protimikrobnost smo testirali s pomočjo izbranih bakterij, fizikalno-kemijske lastnosti pa smo preverili z metodami UV-VIS, SEM, FT-IR in Franz celico. Pridobljeni rezultati kažejo, da so preliminarni poskusi na timpanalnih cevkah cevke s takšnim premazom odlična preventiva pred nastankom biofilma, omogočeno pa bi bilo tudi boljše celjenje (manjša možnost porasta bakterij zaradi protimikrobnega premaza). Amoksiklav je zaradi svoje široke uporabe in dostopnosti primerna izboljšava cevk. Za bolj gotove rezultate bi bilo potrebno opraviti še več ponovitev testiranj ter zamenjava amoksiklava s podobnim zdravilom, saj je amoksiklav zaradi svoje slabe stabilnosti precej problematičen za uporabo. Silicones are widely used materials which can also be used as part of tympanostomy tubes, where the goal is to further advance the functional surface of the tubes in a way that would enhance the healing processes of ear inflammations and other ear diseases where such tubes are used. The master’s thesis focuses on the treatment of silicone surfaces with various antimicrobial coatings. We prepared coatings made of nanoparticles and added amoxiclav, or, alternatively, the nanoparticles contained only triphosphate and chitosan which are both able to spontaneously form nanoparticles. The size of the particles was measured using the DLS method (dynamic light scattering), stability of the dispersion was checked with measurements of Zeta potential, antimicrobial properties were tested using selected bacteria, and physical and chemical properties were checked using the UV-VIS method (ultraviolet-visible spectroscopy), SEM method (scanning electron microscopy), FT-IR method (Fourier-transform infrared spectroscopy), and the Franz cell (in vitro release). The results show that preliminary tests with tympanostomy tubes with the selected coatings are excellent prevention against the occurrence of a biofilm, plus it enabled better healing (reduced likelihood of a growth of bacteria due to the antimicrobial coating). Due to its wide spectre of use and high accessibility, amoxiclav is a suitable addition to the tubes. In order to get more definitive results, we’d need repeat testings and amoxiclav should be replaced with a similar medicinal product since its use is relatively problematic due to its lack of stability.

Namen diplomskega dela je bil preučiti adsorpcijske lastnosti biooglja, pridobljenega iz odpadne biomase s postopkom hidrotermične karbonizacije (HTC), za adsorpcijo težkih kovin, in sicer Cd2+ in Pb2+ ionov. Kot odpadni biomaterial smo uporabili lubje listavca z velikim deležem taninov, skorjo kostanja. Določili smo izkoristek biooglja pridobljenega s HTC ter izmerili zeta potencial, specifično površino, volumen por, povprečni premer por in velikost delcev. Biooglje smo pripravili brez in z dodatkom ocetne kisline in rezultate med seboj primerjali. Povprečni izkoristek in masa obeh pridobljenih vzorcev sta bila podobna. Nato smo izvedli ravnotežno adsorpcijo Cd2+ in Pb2+ ionov v odvisnosti od pH in koncentracije izhodne raztopine. Ravnotežna adsorpcija Pb2+ ionov v odvisnosti od pH je bila najboljša pri pH 2. Maksimalna kapaciteta adsorbenta za svinčeve ione je bila dosežena pri koncentraciji 12 mM in je znašala 151,80 mg/g adsorbenta. Adsorpcija Cd2+ ionov je bila najvišja pri pH 5, vendar je bila količina adsorbiranih ionov mnogo nižja kot Pb2+ ionov. Največjo specifično površino je imelo biooglje brez dodatka ocetne kisline, in sicer 12,8229 m2/g. Najnižjo vrednost zeta potenciala -19,00 mV je imel vzorec zdrobljenega biooglja, pridobljenega z dodatkom ocetne kisline. Velikost delcev je bila najvišja pri nezdrobljenih delcih biooglja. V tem primeru je imelo največji povprečni premer biooglje pridobljeno brez dodatka ocetne kisline, in sicer 3248 nm. The purpose of this thesis was to study the adsorption properties of biochar derived from waste biomass by the hydrothermal carbonization process (HTC) for the adsorption of heavy metals, i.e., Cd2+ and Pb2+ ions. As a waste biomaterial, we used the bark of deciduous trees with a high proportion of tannins, which is a chestnut. We determined the yield of biochar obtained with HTC and measured the zeta potential, the specific surface area, the pore volume, the average pore diameter, and the size of the particles. Biochars were prepared without and with the addition of acetic acid, and the results were compared. The average yield and mass of the two obtained samples were similar. Then we equilibrated the adsorption of Cd2+ and Pb2+ ions depending on the pH and concentration of the starting solution. The equilibrium adsorption of Pb2+ ions in pH dependence was best at pH 2. The maximum lead adsorbent capacity was reached at a concentration of 12 mM and amounted to 151.8 mg/g of adsorbent. Adsorption of Cd2+ ions was highest at pH 5, but the amount of adsorbed ion was much lower than Pb2+ ions. The largest specific surface area had biochar without the addition of acetic acid, which amounted to 12.8229 m2/g. The minimum value of the zeta potential of -19,00 mV was the sample of broken biochar obtained with the addition of acetic acid. The particle size was the highest in non-fragmented biochar particles. In this case, the maximum average diameter of biochar was obtained without acetic acid addition, which amounted to 3248 nm.

Osrednji namen diplomskega dela je študija vpliva tlaka na kristalno strukturo izločenega CaCO3 iz vodne raztopine. Za ta namen smo izvedli štiri različne načine izparevanja, in sicer izparevanje z rotavaporjem, tlačno posodo, izparevanjem pri atmosferskem tlaku pri 40 °C in pri 100 °C. Izvedli smo tudi izparevanje s prisotnim zaviralcem rasti CaCO3 – magnezijevimi ioni. V nalogi smo se omejili na merjenje absorbance, motnosti, pH vrednosti, zeta potenciala in velikosti delcev, takoj po nastali suspenziji v modelni raztopini in vodovodni vodi. Izločene kristale smo analizirali s pomočjo rentgenske praškovne difrakcije. Ugotovili smo, da tlak vpliva na lastnosti CaCO3, vendar ne takoj po nastanku oborine. Spremembe so se pričele nekje po 15 minutah obdelave vzorcev. Pri vseh eksperimentih se je izločal kalcit. Pri obdelavi vodovodne vode, v tlačni posodi, se je izločil tudi aragonit, a se je kasneje modificiral v kalcit. Aragonit smo zasledili še pri dodatku MgCl2. The main problem of our thesis is the influence of pressure on the crystalline properties of CaCO3 precipitate from aqueous solution. For this study we carried out four different ways of evaporation: with rotary evaporator, with pressure vessel and evaporation at atmospheric pressure at 40 °C as well as 100 °C. We carried out the evaporation with the present inhibitors of the growth of CaCO3 – magnesium ions. In this paper, we limited ourselves to the measurement of absorbency, turbidity, pH value, zeta potential and particle size immediately after the precipitation of CaCO3 from model solution and tap water. We analyzed the excreted crystals with the help of XRD. We have concluded that pressure affects the properties of CaCO3 but not immediately after precipitation of CaCO3. The changes began after 15 minutes of sample processing. Calcite was excreted in all experiments. The treatment of tap water in pressure vessel also made the aragonite to excrete, although later aragonite modified into calcite. Aragonite was also found in the additive of MgCl2.

V raziskavi smo preučevali elektrokinetične lastnosti poliamida 6 v obliki (a) folije in (b) tekstilnega filamenta ob uporabi dveh merilnih celic. Merili smo potencial zaradi pretoka in iz tega določili zeta potencial (▫$zeta$▫ v odvisnosti od pH vrednosti medija. Meritve na posameznem materialu smo preučevali s stališča ponovljivosti. S tem namenom smo opravili meritve na 10 preskušancih istega vzorca. Določili smo osnovne statistične pokazatelje ponovljivosti za ▫$zeta$▫ pri pH 3 in 9 ter izoelektrično tocko. Metodo smo optimirali glede na čas nabrekanja v raztopini elektrolita pred meritvijo in maso materiala v cilindrični celici. Meritve v 0,001 M KCl na obeh vrstah materiala kljub različni nadmolekulski in površinski strukturi dobro sovpadajo. Krivulje ▫$zeta$▫=▫$zeta$▫(pH) imajo pričakovan potek. PA 6 kaže amfoterno naravo zaradi vsebnosti amino in karboksilnih skupin. V alkalnem mediju disociirajo karboksilne skupine, kar povzroči negativen ▫$zeta$▫ (folija: (-32,9▫$pm$▫ 1,6) mV, filament: (-35,2▫$pm$▫2,0) mV pri pH 9). V kislem mediju kaže PA kationski značaj zaradi disociacije amino skupin (folija: (24,5▫$pm$▫1,7) mV, filament: (15,1▫$pm$▫1,1) mV pri pH 3). Izoelektrična točka, kjer je ▫$zeta$▫ enak 0, se nahaja za folijo pri pH vrednosti 4,7▫$pm$▫0,1, za filament pa pri 4,9▫$pm$▫ 0,1. This paper investigates electrokinetic properties of polyamide 6 in a form of (a) foil and (b) textile filament using two measurement cells. The streaming potential was measured and the zeta potential ▫$zeta$▫ as a function of the pH value of medium was determined. The reproducibility of measurements was determined with 10 samples of each material. The basic statistics regarding ▫$zeta$▫ at pH of 3 and 9 and isoelectric point (IEP) were determined. Furthermore, the wetting time in the electrolyte solution before the measurement and the mass of material in cylindrical cell were optimized. The measurements in 0.001 M KCl on both materials coincide with each other quite well in spite of different supermolecular and surface structure. The ▫$zeta$▫-pH curves show the expected form. PA 6 is amphoteric due to presence of the amino and carboxyl groups. In the alkaline environment the carboxyl groups dissociate thus the ▫$zeta$▫ is negative (foil: (-32.9▫$pm$▫1.6)mV, filament: (-35.2▫$pm$▫2.0) mV at pH of 9). In the acid environment PA 6 shows a cationic nature due to the dissociation of the amino groups (foil: (24.5▫$pm$▫1.7) mV, filament: (15.1▫$pm$▫1.1) mV at pH of 3). The isoelectric point, where f is equal to 0, was found for foil at pH value of (4.7▫$pm$▫0.1) and for filament at (4.9▫$pm$▫0.1), respectively.

Sintetizirali smo flokulante iz različnih vrst tanina. Za sintezo smo uporabili tanin smreke, smreke-jelke, hrasta, mimoze, alepskega bora in kvebrača ter ustrezne kemikalije. Osnova za pridobivanje kationskih flokulantov je bila Mannichova reakcija, ki smo jo izvajali v digestoriju ob stalnem mešanju pri konstantni temperaturi. Testiranje flokulantov je potekalo na standardizirani napravi floktester. Zeta potenciale smo izmerili na zetametru Laser zeetm 501. Various kinds of tannin flocculants were synthesised using spruce tannin, spruce-fir tannin, oak tannin, mimosa tannin, aleppo pine tannin, quebracho tannin, with suitable chemicals. Cationic flocculants were obtained on the basis of the Mannich reaction performed at constant mixing and constant temperature. The testing of flocculants was performed by standardised flock tester. Zeta potentials were measured using Laser Zeetm 501 zeta meter.

Kompozitni nanodelci, ki vsebujejo superparamagnetno maghemitno jedro, prevlečeno s tanko plastjo amorfnega silicijevega oksida so zelo obetaven material za uporabo v biomedicini. Magnetno jedro omogoča manipulacijo z delci z zunanjim magnetnim poljem, medtem ko plašč amorfnega silicijevega oksida omogoča vezavo različnih molekul na njihovo površino. Vezava različnih organskih molekul, na primer zdravilnih učinkovin, zahteva pripravo nanodelcev, ki imajo na površini sloj funkcionalizacijskih molekul z različnimi funkcionalnimi skupinami. Funkcionalizacijo nanodelcev smo dosegli s kovalentno vezavo različnih silanskih molekul: (3-aminopropil)trietoksisilan (APS) in viniltrietoksisilan (VTS), na njihovo površino. Reakcija je potekla v mešanici etanola, v katerem je bila predhodno raztopljena izbrana silanska molekula, in stabilne vodne suspenzije kompozitnih nanodelcev. Vezavo različnih silanskih molekul na površino nanodelcev smo spremljali z elektrokinetičnimi meritvami in s konduktometrično meritvijo koncentracije molekul na njihovi površini. Izkazalo se je, da lahko vežemo na delce molekule APS v površinski koncentraciji, ki se sklada s koncentracijo silanolnih skupin na površini amorfnega silicijevega oksida. Composite nano-particles of superparamagnetic maghemite particles coated with a thin layer of silica are very promising material for biomedical applications. The magnetic core of the composite nano-particles allows manipulation of particles with external magnetic field while the silica shell allows additional bonding of molecules to the surface. Different organic molecules, such as medical drugs, require nano-particles with a layer of functionalization molecules with different functional groups. The functionalization of nano-particles was achieved with covalent bonding of different silanol molecules: (3-aminopropyl) triethoksysilane (APS) and vinyltriethoksysilane (VTS) to their surface. Reaction took place in a mixture of ethanol with previously dissolved silane and stable aqueous suspension of composite nano-particles. The bonding of different silanol molecules was monitored with electro-kinetic measurements and with conductometric measurements of molecules on the surface. The concentration of APS molecules which can be bondend to the surface of the composite nano-particles is in accordance with the concentration of silanol groups on the surface of silica.

Namen magistrske naloge je sintetizirati in karakterizirati biooglje, ki smo ga dobili iz odpadne biomase s pomočjo subkritične vode. Sinteza biooglja je potekala v subkritični vodi z različnimi odpadnimi materiali in z dvema različnima plinoma za vzpostavitev atmosfere v reaktorju, N2 in CO2. Temperature sinteze pri tem nismo spreminjali in je vedno znašala 225 °C. Da bi ugotovili vpliv sušenja na lastnosti biooglja, smo uporabljali klasični termični postopek sušenja in metodo s superkritičnim CO2. Določili smo izkoristek sinteze biooglja različnih materialov in dobljenim vzorcem določili zeta potencial, z adsorpcijo dušika smo izmerili specifično površino, volumen in povprečni premer por. Vsem vzorcem smo posneli tudi FTIR spekter. Vse rezultate smo primerjali tudi z lastnostmi komercialno dosegljivega aktivnega oglja. Rezultati kažejo na najvišje izkoristke biooglja, ko smo za začetni material izbrali zmleto in z vodo predhodno ekstrahirano macesnovo skorjo. Pri teh pogojih smo dosegli 68,3 % izkoristek biooglja, ko smo uporabili dušik kot plin za vzpostavitev tlaka v sistemu, medtem ko smo pri vzorcu, ki je bil sintetiziran pri istih pogojih, a se je pri tem uporabil CO2, dobil produkt bolj enakomernejše oblike. Izkoristek biooglja pri uporabi CO2 kot plina za vzpostavitev tlaka v reaktorju je bil nekoliko nižji, in sicer 66,5 %. Rezultati merjenja zeta potenciala kažejo na to, da ima najnižji zeta potencial biooglje dobljeno iz mlete in v vodi predhodno ekstrahirane macesnove skorje, pri tlaku 215 bar, pri podaljšanem reakcijskem času tj. 6 h. Zeta potencial tega produkta znaša -34,33 mV. Največjo specifično površino vzorca smo dosegli pri biooglju macesnove skorje, ki je bil sušen s postopkom superkritičnega sušenja. Pri teh pogojih smo dobili specifično površino vzorca, ki je znašala 225,82 m2/g. Specifična površina aktivnega oglja je znašala 886,53 m2/g. FTIR spektri kažejo, da so si vzorci po sestavi med seboj zelo podobni in da je vpliv različnih plinov na površinske funkcionalne skupine majhen. Razlika se kaže le v prisotnosti O-H vezi, kar kaže na različno pripravo vzorcev. The purpose of the master's thesis is to synthesize and characterize biochar, which was obtained from waste biomass using subcritical water. The synthesis of biochar was conducted insubcritical water with a variety of materials, using two different gases, namely N2 and CO2. The temperature of synthesis was not changed and was always set to 225 °C. In order to determine the influence of drying on the properties of biochar, the classical thermal air-drying method and the method with supercritical CO2 were used. The yield of biochar of different biowaste materials was determined and for the obtained products the zeta potential was measured. Furthermore, the specific surface area, average pore volume and diameter was determined using the nitrogen adsorption method. For all obtained biochar samples the FTIR spectra were measured. All obtained results were compared to the properties of commercially available activated carbon. Results show that the highest biochar yield was obtained for grinded and with water are extracted larch bark. At these conditions a maximal yield of 68.3% was obtained, when nitrogen was used as the gas for maintaining the pressure inside the reactor,. On the other side, the biochar that was synthesized at the same conditions but instead CO2 was used had more evenly distributed particle size. At these conditions, 66.5 % of the starting material could be converted into biochar. Results from the measurement of the zeta potential have shown that the lowest zeta potential was obtained for the larch bark biochar that was before the synthesis grinded and extracted, and afterwards treated in subcritical water at 215 bars and at a reaction time of 6 hours. The zeta potential of this product was -34.33 mV. The highest specific area of a sample was obtained for larch bark, which was dried using the supercritical drying method. At these conditions a specific area of 225.82 m2/g could be obtained. The specific area of activated carbon was 886.53 m2/g. The FTIR spectra have shown that the obtained samples are similar to each other. There are no significant differences in the surface funcional groups between the samples when different gases are used. The difference is only in of O-H bonds, which indicates the difference in preparation of the samples.

Namen raziskave je preučiti vpliv različnih procesnih dejavnikov, na učinkovitost procesa ultrafiltracije oljno-vodne emulzije. Preučili bomo vpliv obratovalnih parametrov kot so tlak, temperatura in pH vrednost ter preizkusili polimerno polietersulfonsko (PES) membrano za čiščenje oljno-vodne emulzije pri procesu čelnega sistema ultrafiltracije. Namen je tudi preučiti medsebojni vpliv zeta potenciala polimerne ultrafiltracijske PES membrane in velikosti delcev oljnih kapljic v emulziji. V raziskavi magistrske naloge smo izvajali čiščenje oljno-vodne emulzije z ultrafiltracijo pri različnih obratovalnih parametrih. Preverili smo učinkovitost zadržanja delcev na površini PES membrane med čiščenjem oljno-vodne emulzije. Pri merjenju zeta potenciala smo ugotavljali stabilnost oljno-vodne emulzije ter vpliv pH vrednosti na zeta potencial PES membrane. Rezultati raziskave so pokazali, da čelna tehnika ultrafiltracije ni najbolj primerna metoda za čiščenje oljno-vodne emulzije zaradi številnih zamašitev PES membrane, tako ireverzibilnih kot tudi reverzibilnih, ki so posledično znižale gostoto volumskega toka permeata. Ugotovili smo, da je PES membrana uspešno zadržala večino delcev oljnih kapljic med ultrafiltracijo, vendar se je zaradi hidrofobnega značaja močno mašila in je ni bilo možno očistiti do te mere, da bi bila primerna za nadaljnjo uporabo. Ugotovili smo, da ima pH vrednost največji vpliv na zeta potencial zaradi interakcij med negativno nabito PES membrano in negativnimi oljnimi kapljicami, zato je pri pH=9 možen najlažji prehod oljnih kapljic skozi membrano in so pretoki višji. Z višjim pH smo dosegli večjo stabilnost oljno-vodne emulzije. Potrdili smo, da PES membrana nima izoelektrične točke in da ima PES membrana negativni zeta potencial v celotnem pH območju, ki med pH 8 in 9 doseže najnižjo vrednost. The purpose of the research was to examine the influence of different factors on the efficiency of the ultrafiltration separation of oil-in-water emulsion. We will examine the influence of operating process parameters such as pressure, temperature and pH value. We will test the polymeric polyethersulfone (PES) membrane for cleaning of oil-in-water emulsion with dead-end ultrafiltration. The purpose is also to examine the interaction between the zeta potential of the polymeric ultrafiltration PES membrane and the particle size of the oil droplets in the emulsion. In the frame of the master's thesis the oil-in-water emulsion was treated by ultrafiltration independance of the different operating parameters. The effectiveness of retention of particles at the PES membrane surface during the cleaning of oil-in-water emulsion was studied. The stability of the oil-in-water emulsion was determined with zeta potential measurement. The influence of pH value on the zeta potential of the PES membrane was investigated. The results showed that the dead-end ultrafiltration is not the most appropriate method for oil-in-water emulsion treatment because of many different types of fouling of the PES membrane, such as irreversible and reversible, and consequently flux permeate declined. We have found that the PES membrane successfully retain most of the particles of oil droplets during the ultrafiltration, but regarding the strong hydrophobic characteristic of the membrane it could not be cleaned to that extend suitable for reuse. We also have found that the pH value has the major influence on the zeta potential regarding interactions between the negatively charged PES membrane and negative charge of oil droplets. At pH=9 oil droplets easily travel through the PES membrane and fluxes are higher. The higher the pH, the higher stability of the oil-in-water emulsion. We confirmed that the PES membrane has no isoelectric point and the membrane has negative zeta potential over the entire pH range. The lowest value of the zeta potential was reached between pH values 8 and 9.

Sintetizirali smo flokulante iz različnih vrst tanina. Za sintezo smo uporabili tanin smreke, smreke-jelke, hrasta, mimoze, alepskega bora in kvebrača ter ustrezne kemikalije. Osnova za pridobivanje kationskih flokulantov je bila Mannichova reakcija, ki smo jo izvajali v digestoriju ob stalnem mešanju pri konstantni temperaturi. Testiranje flokulantov je potekalo na standardizirani napravi floktester. Zeta potenciale smo izmerili na zetametru Laser zeetm 501. Various kinds of tannin flocculants were synthesised using spruce tannin, spruce-fir tannin, oak tannin, mimosa tannin, aleppo pine tannin, quebracho tannin, with suitable chemicals. Cationic flocculants were obtained on the basis of the Mannich reaction performed at constant mixing and constant temperature. The testing of flocculants was performed by standardised flock tester. Zeta potentials were measured using Laser Zeetm 501 zeta meter.

Za doseganje protimikrobnih lastnosti tekstilnih materialov obstajajo številne metode funkcionalizacij. Pri večini teh metod se še zmeraj uporabljajo reagenti, ki so človeku in okolju neprijazni, saj lahko vsebujejo anorganske soli, fenole in tiofenole, antibiotike, derivate formaldehida, itd. Zlasti aktualen na področju funkcionalizacije tekstilij je hitozan. Tako kot v farmaciji in kozmetiki je tudi na področju razvoja medicinskih tekstilij trend v uporabi nanodelcev za doseganje funkcionalnosti vlaken oz. tkanin. Tako imajo nanodelci hitozana kot adsorbat za tekstilijo številne prednosti pred samo raztopino hitozana. Namen naloge je bil izvesti primerjavo med hitozanom in nanodelci hitozana z vidika potencialne uporabnost hitozana kot adsorbata za funkcionalizacijo površin celuloznih vlaken. Izvedeni so bili postopki adsorpcije hitozana in nanodelcev hitozana iz tekočega medija na površino celulozne matrice. Funkcionalizirana celulozna vlakna so okarakterizirana s fizikalno-kemijskega kot tudi protimikrobnega značaja. Ugotovili smo, da se nanodelci hitozana v primerjavi s hitozanom (aminske skupine) na površino vlaken adsorbirjo v večji količini in ima večjo vsebnost dostopnih aminskih skupin, ter tako dajejo posledično boljše protimikrobne učinke. To achieve the antimicrobial properties of textile materials, there are many methods of functionalization. In most of these methods are still used reagents for human and environment not friendly, as they may contain inorganic salts, phenols and tiofenole, antibiotics, derivatives of formaldehyde, etc. Particularly topical in the functional treatments is chitosan. Just as in the pharmaceutical and cosmetics is also in the field of medical textiles trend in the use of nanoparticles to achieve the functionality of fiber or fabric. Chitosan nanoparticles as adsorbate to textiles has numerous advantages over the solution of chitosan. The purpose of this thesis is to carry out a comparison between the chitosan and chitosan nanoparticles regarding potential use of chitosan as an adsorbate for fuctionalization of cellulose matrix. We performed procedures of chitosan adsorption from a liquid medium to the cellulose matrix. The physical-chemical (determining the functional group of the fibres) and antimicrobial properties of functionalized cellulose fibres have been characterised. We concluded that chitosan nanoparitcles, if compared to the chitosan (amino groups), adsorbs a larger quantity on the fibre surface and has a higher content of available amino groups and consequently better antimicrobial effects.

Namen diplomske naloge je preučiti vpliv kemičnih vlaken v bombažnih in volnenih vzorcih na potencial zeta. Vzorci, ki smo jih dobili iz dveh tekstilnih podjetij Beti preja d.o.o. in Galeb d.d. so bili različnih sestav bombaž/modakril in volna/viskoza/poliamid. Potencial zeta je parameter, ki odraža medfazne lastnosti in je zelo pomemben za razumevanje vedenja trdnih snovi v številnih tehničnih postopkih. To daje vpogled v naboj in adsorpcijske lastnosti trdnih površin. Potencial zeta opisuje elektrokinetične lastnosti na meji trdno/tekoče, kjer pride do interakcij med trdno in tekočo fazo. Ta medfazna površina je opisana s kemičnim in elektrokemičnim potencialom, ki je popolnoma drugačen, kot tisti v čisti tekoči oz. trdni fazi, saj na molekule na meji vplivajo interakcijske sile iz obeh prisotnih faz. Za določitev potenciala zeta smo uporabili elektrokinetični analizator SurPASS proizvajalca Anton Paar GmbH iz Gradca v Avstriji, ki nam s pomočjo programske opreme »Visiolab for SurPAS« izračuna potencial zeta iz merjenega pretočnega potenciala. Za merjenje potenciala zeta smo uporabili cilindrično celico za vzorce prej in pravokotno merilno celico z nastavljivo režo za merjenje pletenin. Merili smo pretočni potencial za določitev potenciala zeta vzorcem sestave bombaž/modakril in volna/viskoza/poliamid. Iz dobljenih podatkov potenciala zeta v odvisnosti od pH vrednosti smo ovrednotili podatke in preučili vpliv kemičnih vlaken na potencial zeta. The intention of diploma work was to study the influence of chemical fibres on zeta potential in regard to cotton and woollen samples. These samples were obtained from two textile companies, Beti preja d.o.o. and Galeb d.d., and contained different compositions cotton/modacryl and wool/viscose/polyamide, respectively. Zeta potential is a parameter that reflects the characteristics of solid/liquid interfaces, and is very important for understanding the behaviours of solids within several technical processes. This provides an insight into the charge and adsorption properties of a solid’s surfaces. Zeta potential describes those electro-kinetic properties on the borders of a solid/liquid, where interaction takes place between the solid and liquid phases. This interface is described by chemical and electrochemical potential, which is completely different to that in bulk liquid or solid phases, since the molecules on the borders affect the interaction forces from both phases. The electro-kinetic analyzer SurPASS produced by Anton Paar GmbH from Graz, Austria was used to calculate the zeta potential. With the help of »Visiolab for SurPASS«, the software of SurPASS, the zeta potential was calculated from the measured streaming potential and streaming current. Two measuring cells were used for measuring the zeta potential. Cylindrical cell was used for measuring the yarn samples and adjustable gap cell for measuring the knitwear. The measurements were based on modelled structure of cotton/modacrylic and wool/viscose/polyamide. From the data obtained, zeta potential versus pH data was evaluated, and impacts of chemical fibres on the zeta potential were examined.

Potencial zeta je eksperimentalno določljiva veličina in je rezultat delovanja elektrokinetičnih pojavov. Nanaša se na spremembo potenciala na strižni površini med premikajočim in mirujočim delom difuzne dvojne plasti. Namen diplomske naloge je bil ugotoviti kako gostota zloženosti prej v cilindrični celici vpliva na potencial zeta in kakšen vpliv ima nanj širina reže pretočnega kanala v celici z nastavljivo režo. Ugotavljali smo tudi ali so rezultati potenciala zeta prej in pletenin med seboj primerljivi. V naši raziskavi smo potencial zeta določali z elektrokinetičnim analizatorjem SurPASS, ki temelji na merjenju pretočnega toka in pretočnega potenciala. Z uporabo tega instrumenta je mogoče dobiti tudi informacijo o realnem potencialu zeta, in ne le o navideznem. Rezultati merjenj v cilindrični celici so pokazali, da z naraščajočo gostoto zloženosti postaja potencial zeta vse manj negativen. Rezultati merjenj v celici z nastavljivo režo pa so pokazali, da širina reže pretočnega kanala, z izjemo 100% modakrila, ne vpliva na potencial zeta. S primerjavo rezultatov potenciala zeta prej in pletenin smo ugotovili, da celici dajeta primerljive rezultate navideznega potenciala zeta. Ugotovili smo tudi, da realni in navidezni potencial zeta nista primerljiva zaradi velikih razlik v absolutnih vrednostih. Za informacijo o realnem potencialu zeta bo raziskavo potrebno nadaljevati z merjenjem v modificirani celici z nastavljivo režo. Rezultati merjenj v cilindrični celic in celici z nastavljivo režo so potrdili pričakovan trend vzorcev glede na vsebnost bombaža in modakrila, in sicer da s povečano vsebnostjo modakrila potencial zeta postaja vse bolj negativen. The zeta potential is an experimentally determinable parameter and is the result of electrokinetic phenomena. It refers to the potential change on shear surface between the moving part and the static part of the diffuse double layer. The aim of the thesis was to determine the effect of packing density of yarn in a cylindrical cell on zeta potential and what impact it has the width of slit in the streaming channel in an adjustable gap cell on zeta potential. We also wanted to determine whether or not the results of zeta potential measurements of yarn and knitted fabrics are comparable. In our study, zeta potential was determined with using a »SurPASS« electrokinetic analyzer based on the streaming current and streaming potential measurement. By using this instrument is it also possible to get informations about the correct zeta potential, and not just for the apperent zeta potential. The results of measurements in the cylindrical cell have shown that the higher the packing density, the less negative the zeta potential. The results of measurements in the adjustable gap cell have demonstrated that the width of the slit in the streaming channel, with the exception of 100% modacrylic, does not affect the zeta potential. When comparing the zeta potential results of yarn and knitwear, it was determined that the results of apparent zeta potential are comparable between both cells. It was also determined that the apparent and correct zeta potential are not comparable due to large differences in absolute values. In order to obtain accurate information on the correct zeta potential, all further measurements shall be performed in a modified adjustable gap cell. The results of measurements in the cylindric and adjustable gap cell confirmed the expected trend of samples, namely depending on the content of cotton and modacrylic – the higher the content of modacrylic, the more negative the zeta potential.

IZBIRA MATERIALA ZA KONTROLO KAKOVOSTI POTENCIALA ZETA TRDNIH POVRŠIN Povzetek Zanesljive rezultate meritev lahko zagotovimo le z brezhibnim delovanjem merilnih naprav, katerih zmogljivost pa se s časom in uporabo slabša. Pravilno delovanje merilne naprave lahko preverimo z referenčnim materialom. Tudi elektrokinetični analizator SurPASS, ki je na tržišču relativno kratek čas, je podvržen različnim vplivom in potrebuje material za kontrolo kakovosti potenciala zeta. Instrument SurPASS namreč omogoča merjenje pretočnega toka, s katerim določimo t.i. potencial zeta, ki določa stanje površinskega naboja na mejni površini trdnega telesa in tekočine. Izbire trdnega materiala z ravno površino, ki je primeren za merjenje v merilni celici CLC, smo se lotili z meritvami časovne odvisnosti potenciala zeta na polimerih (PTFE, PES in PET) ter steklu. Najbolj stabilne meritve dajeta vzorca PES in PET, ki sta glede na dobljene rezultate konstante hitrosti nabrekanja tudi najbolj hidrofobna. Zato smo meritve nadaljevali na teh dveh materialih. Statistična analiza rezultatov teh meritev nakazuje na homogenost obeh materialov, čeprav v nekaterih primerih daje prednost materialu PES, spet drugič PET. Takšne nasprotujoče si rezultate meritev lahko pripišemo tudi napakam v meritvah (omočenost nemerjene površine vzorca v CLC) in ne nujno nehomogenosti materiala. MATERIALS SELECTION FOR THE ZETA POTENTIAL QUALITY-CONTROL OF SOLID SURFACES Abstract Reliable results of measurements can only be assured by using faultless measuring instruments, the efficiencies of which do, regrettably, deteriorate over time and usage. The correct functioning of instruments can be examined using reference materials. The SurPASS electrokinetic analyser, which has only been on the market for a relatively short time, is also subject to different influences and therefore needs a material for zeta potential quality control. The SurPASS instrument enables the measurement of streaming-current which helps us to determine the so-called zeta potential, which then indicates the status of the surface-charge on the border area of a solid or liquid. We began by selecting a solid material with a flat surface, which would be suitable for the CLC measuring cell, using the measurements of time-dependence regarding zeta potential on polymers (PTFE, PES and PET), and glass. The more stable measurements were given for samples PES and PET, for which it provided the more constant results, and also the most hydrophobic materials. Consequently, we continued our measurements on the afore-mentioned two materials. Statistical analysis of these results indicated the homogeneities of both materials although, in some cases, it gave an advantage to PES, and then the second time to PET. These kinds of contradictive measurement results can also be annotated to mistakes during the measuring process (wettability of the non-measured surface sample in CLC), and not necessarily to any non-homogeneity of the material.

Elektrokinetične lastnosti opišejo električni potencial v bližini trdne površine, ki se premika v tekoči fazi. Opisan je z zeta potencialom. Avstrijsko podjetje Anton Paar GmbH iz Graza je razvilo elektrokinetični analizator SurPASS, ki temelji na principu merjenja pretočnega potenciala in pretočnega toka za določanje zeta potenciala. V tekstilni industriji so v uporabi večnamenske apreture za aplikacijo tehnologije mikrokapsuliranja na tekstilijah, katerim lahko izmerimo pretočni potencial, na osnovi tega pa določimo zeta potencial, s katerim lahko ovrednotimo lastnosti površin bombažnim in poliamidnim pleteninam. Namen diplomskega dela je raziskava vpliva mikrokapsuliranih in apreturnih sredstev bombažnih in poliamidnih (PA6,6) vzorcev na zeta potencial (ZP), v odvisnosti od pH elektrolita. Ob tem smo proučevali vpliv pralnih ciklov na obstojnost mikrokapsul in apreturnih sredstev. Raziskovali smo lastnosti bombažnih pletenin in poliamidnih prej in pletenin. Iz rezultatov meritev pretočnega potenciala je razvidno, da je pri bombažnih vzorcih po 10 kratnem ciklu pranja zelo povečana hidrofilnost, saj se po pranju spira mehčalec in protimikrobni nanos. Pri poliamidnih vzorcih pa se spirajo mikrokapsule prav tako po 10 kratnem ciklu pranja. Electrokinetic properties describe the electrical potential adjacent to a solid surface, if it is moving in the surrounding liquid phase. It is described by zeta potential. Austrian company Anton Paar GmbH from Graz has developed the SurPASS elektrokinetic analyzer, which is based on a streaming potential/streaming current for determining the zeta potential. Many different apertures for application of micro capsulation technology on textile materials are used in textile industry. Streaming potential was measured, and on the base of it, zeta potential was determined, which is further used for evaluation of cotton and polyamide knitted fabrics surface properties. The aim diploma thesis is studying influence of microencapsulated and chemical agents of cotton and polyamide (PA 6,6) samples on zeta potential (ZP), in correlation with pH of electrolyte. Influence of washing cycles on stability of microcapsules and chemical agents was also studied. It is evident from streaming potential measurement results, that hydrophilic properties are much higher after 10 washing cycles, as during washing softening antibacterial layer is rinsed out. The same situation was also established in polyamide samples, where microcapsules were also rinsed out after ten washing cycles.

Elektrokinetične lastnosti opišejo električni potencial v bližini trdne površine, ki se premika v tekoči fazi. Opisan je z zeta potencialom. Avstrijsko podjetje Anton Paar GmbH iz Graza je razvilo elektrokinetični analizator SurPASS, ki temelji na principu merjenja pretočnega potenciala in pretočnega toka za določanje zeta potenciala. Namen naloge je bil, da z zeta potencialom merjenim na podlagi pretočnega potenciala določamo kakovost vzorčenih surovih bombažnih tkanin pridobljenih iz vzhodnih držav (Kitajska, Indija,…). Kakovost le-teh ima močan vpliv na kakovost končnega produkta. Nizka kakovost zahteva ponovitve procesnih obdelav pri končnih izdelkih ter dodatno zvišuje stroške produktov. Nato smo še določili zeta potencial bombažnih, surovih in obdelanih vlaknin (čiščenje, kislinska in alkalna obdelava, beljenje) z namenom vzpostavitve korelacije med surovimi in obdelanimi bombažnimi tkaninami. Rezultati meritev pretočnega potenciala jasno kažejo na razlike površinskih lastnosti surovih in obdelanih bombažnih vlaknin kjer ima alkalijsko obdelan bombaž največjo dostopnost disociiranih hidroksilnih in karboksilnih skupin na površini, kar vidimo v porastu negativnega zeta potenciala. Elektrokinetic properties describe the electrical potential adjacent to a solid surface, if it is moving in the surrounding liquid phase. It is described by zeta potential. Austrian company Anton Paar GmbH from Graz has developed the SurPASS elektrokinetic analyzer, which is based on a streaming potential/streaming current for determining the zeta potential. Zeta potential measurements using this streaming potential method were performed regarding the quality of the supplied raw cotton fibres from east countries (China, India,… ). The quality of the raw cotton fibres has a strong influence on the final product. Low- quality cotton requires the repetition of different process steps, which increases production costs. We determined the zeta potential of cotton-knitted fabrics, both raw and modified (de-waxed, acid and alkali treated and pre-bleached), in order to establish any correlation between the raw and treated cotton knitted fabrics. The streaming potential measurements clearly showed the differences in the surface properties between the raw and modified cottons. The alkali pre- treatment caused a pronounced decrease in zeta potential, and an improvement in the accessibility of dissociable groups of cotton knitted fabrics.