Search

This article presents green in situ synthesis of ZnO directly on polyethylene terephthalate (PET) fabrics using pomegranate peel extract. The surface of PET was activated by environmentally friendly oxygen plasma, and the process was compared to alkali treatment where the extract of wood ash was used instead of classical chemicals. Sorption analysis showed that the hydrophilic character of the plasma-treated sample was much better than that of the alkali-treated and untreated samples. Both treatments slightly decreased the breaking strength and elongation of the fabric. Scanning electron microscopy, colour measurements, dispersive X-ray spectroscopy, and antioxidant activity investigations showed that the ZnO particles were successfully synthesised on alkali- and plasma-treated PET. The liquid chromatography-mass spectrometry results showed that ellagic acid and punicalagin were the most abundant compounds in the pomegranate peel extract that enabled the synthesis of ZnO. The UV protection, amount of ZnO, and uniformity were the highest for the ZnO prepared on the PET samples by the plasma-assisted green synthesis. Additional optical assessment of fabric porosity and thickness measurements confirmed that these fabrics have excellent UV protection due to the presence of ZnO.

An extensive study on using plant waste aqueous extracts as natural chemicals for in-situ synthesis of zinc oxide (ZnO) on cotton is presented. Reducing agents were prepared from green tea leaves (GT), pomegranate peels (PG), and staghorn sumac leaves (SsL) and drupes (SsD), and the alkaline medium from discarded wood ash. Zinc acetate was found to be more appropriate precursor than zinc nitrate. Formation of ZnO on cotton was confirmed by energy dispersive spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction analysis (XRD). The inductively coupled plasma mass spectrometry and X-ray fluorescence results showed the highest amount of ZnO on cotton was formed using PG and SsL extracts, which was also confirmed with scanning electron microscopy and UV/visible spectroscopy. The ZnO-functionalised samples exhibited excellent UV-blocking ability and different wetting properties (hydrophilic or hydrophobic) depending on the reducing agent used due to their different total phenolic content. This study shows that by choosing the plant waste source as a reducing agent for ZnO formation directly on cotton, the properties of cotton can be designed to be hydrophilic or hydrophobic with excellent UV-blocking properties. The XRD results of ex-situ synthesis prove that the short reaction time enables the formation of ZnO.

The development of cellulose-based textiles that are functionalised with silver nanoparticles (AgNP), synthesised according to a green approach, and offer protection against ultraviolet (UV) radiation and pathogenic bacteria is very important today. In the present work we demonstrate the environmentally friendly approach to obtain such textile material by AgNP synthesis directly (in-situ) on cotton fabrics, using water extracts of plant food waste (green tea leaves, avocado seed and pomegranate peel) and alien invasive plants (Japanese knotweed rhizome, goldenrod flowers and staghorn sumac fruit) as reducing agents. The extracts were analysed for their total content of phenols and flavonoids and their antioxidant activity. The synthesised AgNP on cotton were round, of different size and amount depending on the reducing agent used. The highest amount of AgNP was found for samples where Japanese knotweed rhizome extract was used as reducing agent and the lowest where extracts of goldenrod flowers and green tea leaves were used. Regardless of the reducing agent used to form AgNP, all cotton samples showed excellent protection againstE. coliandS. aureusbacteria and against UV radiation with UV protection factor values above 50. The best results for UV protection even after the twelve repetitive washing cycles were found for the sample functionalized with AgNP synthesised with an extract of the Japanese knotweed rhizome. Due to the presence of AgNP on cotton, the air permeability and thermal conductivity decreased. AgNP had no effect on the change in breaking strength or elongation of fabrics.Graphic abstract

This research presents a new procedure for the chemical modification of cotton fabric, which included a ‘’green’’ in situ synthesis of silver particles using an extract of sumac leaves as a reducing agent. To increase the adsorption ability of silver cations, a sol-gel matrix was previously created on cotton fabric using an organic–inorganic precursor sol-gel. The presence of silver particles on the cotton fabric was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that silver particles were created on the cotton fabric in the presence of the sumac leaf extract, which colored the fibers in brown. The presence of the sol-gel matrix increased the adsorption of silver cations and therefore the concentration of sliver particles, which resulted in a deeper color yield. Silver particles provided antibacterial protection, with a 99–100% reduction of E. coli in S. aureus bacteria, while the sumac leaf extract provided excellent protection against ultraviolet radiation, with an ultraviolet protective factor equaling 66.54. The coating was also highly durable in terms of its washing fastness.

The development of pH-responsive textile sensors has attracted much interest in recent decades. Therefore, the aim of this study was to show that screen printing could be one of the possible techniques for development of pH-responsive textile. Several parameters that could influence the pH sensitivity and responsivity of a screen-printed textile with bromocresol green dye were studied, such as textile substrate (cotton, polyamide), printing paste composition, and type of fixation (heat and steaming). The change in mechanical and physical properties of the printed fabrics was tested according to the valid ISO, EN, or ASTM standards. The responsiveness of the printed samples to different pH values with the change in colour was evaluated spectrophotometrically. In addition, the colour fastness of the printed textiles to rubbing, washing, and light was also investigated. The results show that the textile responsiveness to pH change was successfully developed by flat screen-printing technique, which proves that the printing process could be one of the methods for the application of indicator dye to textiles. The application of the printing paste to cotton and polyamide fabrics resulted in an expected change in the mechanical and physical properties of the fabrics studied. The responsiveness of printed fabrics to the change of pH value depends on the type of fibres, the strength of dye–fibre interactions, and the wettability of the fabric with buffer solutions. The colour fastness of the printed fabrics to dry and wet rubbing is excellent. Printed polyamide fabric is more resistant to washing than printed cotton fabric. Both printed fabrics have poor colour fastness to light.

Cotton fabric was exposed to low-pressure capacitively coupled plasma to enhance the adsorption and adhesion of fragrance microcapsules (FCM). Two plasma-forming gases, namely oxygen (O2) and nitrogen (N2), were investigated. The untreated and plasma-treated samples were investigated for their morphological changes by scanning electron microscopy (SEM), mechanical properties (breaking force, elongation, and flexural rigidity), and wicking properties. The cotton samples were functionalized with FCM and the effect of plasma pretreatment on the adsorption and adhesion of FCM was evaluated using SEM, air permeability, fragrance intensity of unwashed and washed cotton fabrics, and Fourier transform infrared spectroscopy (FTIR). The results show that the plasma containing either of the two gases increased the wicking of the cotton fabric and that the O2 plasma caused a slight etching of the fibers, which increased the tensile strength of the cotton fabric. Both plasma gases caused changes that allowed higher adsorption of FCM. However, the adhesion of FCM was higher on the cotton treated with N2 plasma, as evidenced by a strong fragrance of the functionalized fabric after repeated washing.

The weak photostability of photochromic dyes applied to textile substrates is one of the disadvantages of the broader use of photochromic dyes in the textile industry. Therefore, the influence of optical brightener concentration on both the photocoloration and photostability of cotton fabric coated with photochromic microcapsules using a pad-dry-cure process, as well as the physical-mechanical properties and colorfastness properties, were studied in this research. Coated samples were subjected to different tests according to valid EN ISO standards, namely mass per unit area, fabric stiffness, breaking force and elongation, air permeability, and different colorfastness properties (rubbing, domestic and commercial laundering, and light). Results showed that the coated fabric had higher mass per unit area, stiffness, breaking force and elongation and lower air permeability compared to uncoated fabric, irrespective of the padding bath composition. Coated fabric has better colorfastness to wet than dry rubbing. The colorfastness to washing decreases with the increased number of washing cycles. The use of optical brightener decreases the photocoloration of coated fabric and increases the photostability of coated fabric after the exposure of samples to a Xenotest apparatus for longer than 12 h.

Technical textile materials with multifunctional protective properties represent one of the largest and fast growing segments of the textile industry. Multifunctional water- and oil-repellent and flame-retardant coating on polyester (PES) fabric was prepared in this research using fluoroalkyl-functional siloxane (FAS) as the water- and oil-repellent finishing agent and organophosphonate (OP) as the flame-retardant agent. A finishing solution containing FAS and OP of appropriate concentrations was applied to the untreated and oxygen plasma-treated PES fabric samples using the pad-dry-cure method. For comparison, single-component FAS and OP finishing solutions were applied to the fabric samples under the same conditions. The coated PES samples were washed under standard conditions. The morphological, chemical and functional properties of the coated PES samples were determined with scanning electron microscopy, Fourier transform infrared spectroscopy, wet pick up, liquid contact and sliding angles measurements as well as oil repellence and vertical burning tests. The results reveal that oxygen plasma treatment prior to finishing significantly increased the wettability of the PES fibres, which directly resulted in increased concentration of the absorbed finishing agents. This treatment enabled the creation of PES fabric with simultaneous uperhydrophobic, oleophobic and flame-retardant properties. Although the superhydrophobic and oil-repellent characteristics of the coating were preserved after washing, the flame retardancy was hindered because of the removal of OP in the washing bath.

The purpose of the study is to investigate the possibility of using wine industry wastes, such as red and white grape bagasse, to produce bacterial cellulose (BC) instead of using a costly commercial medium. BC was produced using grape bagasse as a carbon source replacement and the sole nutrient in the medium. The BC films were evaluated for their productivity and water-holding capacity. The BC films were also investigated for their morphology using scanning electron microscopy (SEM), their viscoelastic properties using dynamic mechanical analysis (DMA), and their chemical composition using Fourier-transform infrared spectroscopy (FTIR). Although the use of grape bagasse as the sole nutrient was successful in the preparation of BC, the BC films had inferior viscoelastic properties to other produced BC films. White grape bagasse proved to be an excellent carbon substitute as the production of BC and its water-holding capacity were five times higher and the produced BC films were up to 72% more flexible than the bacterial cellulose produced using standard HS medium.

An overview of recent work on the low-temperature plasma-assisted synthesis of zinc oxide (ZnO) nanoparticles is presented and interpreted in terms of gas-phase and surface reactions with illustrated examples. The thermodynamical nonequilibrium conditions allow the formation of chemically reactive species with a potential energy of several eV, which readily interact with the Zn precursors and initiate reactions leading to the formation of nanoparticles or nanowires. The high-quality nanowires were synthesized from Zn powders only upon interaction with moderately ionized plasma in a narrow range of plasma parameters. This technique is promising for the synthesis of large quantities of nanowires with aspect ratios well above 10, but the exact range of parameters remains to be determined. Apart from the ex situ techniques, the ZnO nanoparticles can be synthesized by depositing a film of precursors (often Zn salts or Zn-containing organometallic compounds) and exposing them to oxygen plasma. This technique is useful for the synthesis of well-adherent ZnO nanoparticles on heat-sensitive objects but requires further scientific validation as it often leads to the formation of a semicontinuous ZnO film rather than nanoparticles. Both low-pressure and atmospheric plasmas are useful in converting the precursor film into ZnO nanoparticles despite completely different mechanisms.

This study presents an eco-friendly protocol for the hydrophilization of polyethylene terephthalate (PET) fabric and the in situ synthesis of ZnO particles. The alkaline medium and reducing agent for ZnO synthesis were prepared as aqueous extracts from wood ash and pomegranate peel, respectively. Due to the hydrophobic nature of the PET fabric, oxygen plasma treatment was included in the process. The influence of plasma treatment in different synthesis steps on the formation of ZnO and consequently on the morphological, colour and ultraviolet (UV) protective properties of the samples was discussed. The study showed that incorporating oxygen plasma treatment before immersing the samples in each solution for the ZnO in situ synthesis (natural alkaline medium of wood ash, zinc salt and natural reducing agent from pomegranate peel) produced PET fabric with the most uniform ZnO layer without visible cracks and the highest UV-blocking ability with a UV protection factor (UPF) of 300+. The colour measurements showed that increasing the number of plasma treatments leads to higher colour strength of the samples. Herein, a novel protocol for the production of protective PET fabrics is presented, which is also an example of a completely environmentally benign textile functionalization process.

Defluorination of polytetrafluoroethylene (PTFE) surface film is a suitable technique for tailoring its surface properties. The influence of discharge parameters on the surface chemistry was investigated systematically using radio-frequency inductively coupled H2 plasma sustained in the E- and H-modes at various powers, pressures and treatment times. The surface finish was probed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements of water contact angles (WCA) showed increased wettability of the pristine PTFE, however, they did not reveal remarkable modification in the surface chemistry of the samples treated at various discharge parameters. By contrast, the combination of XPS and ToF-SIMS, however, revealed important differences in the surface chemistry between the E- and H-modes. A well-expressed minimum in the fluorine to carbon ratio F/C as low as 0.2 was observed at the treatment time as short as 1 s when plasma was in the H-mode. More gradual surface chemistry was observed when plasma was in the E-mode, and the minimal achievable F/C ratio was about 0.6. The results were explained by the synergistic effects of hydrogen atoms and vacuum ultraviolet radiation.

To develop bio-nanocomposites using natural biopolymers, nanocomposite films were prepared based on sodium alginate and kapok nanofibrils (CNFs). CNFs when subjected to TEMPO-mediated oxidation gave rise to cellulose nanocrystals (TOCNCs), with carboxyl groups at the surface (Ka/Kb = 3.64). The differences between the two types of nanocelluloses (nanofibrils and nanocrystals) and their impact in the preparation of bio-nanocomposites, were studied. When incorporated in the matrix, the CNFs particles have the tendency to form surface aggregation (Ka/Kb = 2.37), distorting the alginate network, creating heterogeneous films, with high surface roughness (Sa = 29.37 nm), porosity (Dp = 0.087 cm2/min) and vulnerability to heat. The TOCNCs present good dispersion creating a 3D network, which forms uniform (Dp = 0.122 cm2/min) and homogeneous films, with smooth surface (Sa = 16.83 nm). The ultrasonication treatment facilitated the dispersion improving the interfacial interaction between the reinforcing phase and the matrix. The results show the reinforcement potential of kapok nanocellulose in an industrially and medically important biopolymer, sodium alginate, especially when TOCNCs and ultrasonication were used., Materials science; Nanotechnology; Nanomaterials; Materials characterization; Materials property; Agricultural technology; Nanofibrils; Nanocrystals; TEMPO-Mediated oxidation; Sodium alginate; Kapok fiber; Nanocomposite

This work presents two protocols for the green in situ synthesis of zinc oxide nanoparticles (ZnO-NP) on cotton with the aim to develop sustainable cotton fabric with an ultraviolet protection factor (UPF). The protocols differed in the order of immersing cotton fabric in reactive solutions of three batches, i.e., precursor (0.1 M zinc acetate dihydrate), reducing agent (aqueous extract of Japanese knotweed leaves) and alkali (wood ash waste). The scanning electron microscope (SEM) results showed that ZnO-NP were successfully synthesised on cotton using both protocols; however, only the protocol where cotton was first immersed in alkali, then in the precursor and, lastly, in the reducing agent enabled very high UPF and higher amount of Zn present on the sample. Due to the different order of cotton fabric immersion in the reactive solutions, dissimilar morphology of the ZnO particles was observed, which resulted in different UV blocking abilities of the samples. The antioxidant analysis (DPPH) showed that the natural reducing agent prepared from Japanese knotweed leaves has very high antioxidant activity, which is attributed to phenolic compounds present in the plant. The reflectance spectroscopy results confirmed that the colour yield and colour of the samples did not influence the UPF value. This protocol is an example of green circular economy where waste materials of invasive alien plant species and pellet heating was used as a natural source of phytochemicals, for the direct synthesis of ZnO-NP to develop cotton fabric with UV-protective properties.

The aim of this research was to investigate different parameters of the in situ synthesis of ZnO nanoparticles on cotton in order to achieve a high ultraviolet protection factor (UPF). In the fi rst part of the research the influence of different reducing agents (Na2CO3, KOH, and NaOH) and their molar concentrations (0.1 M and 1 M) on the formation of ZnO nanoparticles and on the UPF values of cotton fabric were studied. The second part of the research was focused on the other parameters of in situ synthesis, such as the synthesis time ratio (time ratio between the treatment of the fabric in the precursor (ZnCl2) and treatment after the reducing agent was added) and drying period duration after the in situ synthesis. Using UV/Vis spectroscopy, high UPF values (UPF 50+) were measured for cotton fabrics where in situ synthesis was performed using NaOH and KOH, both at 1 M molar concentration. Inductively coupled plasma mass spectrometry (ICP-MS) revealed a higher content of zinc on the fabric when NaOH was used. Scanning electron microscopy (SEM) showed that use of this reducing agent resulted in cotton fabric completely covered with small, round shaped nanoparticles. From the second part of the research, it was found that longer treatment times after the reducing agent was added produced functionalised cotton fabric with higher UPF values. The drying period duration after in situ synthesis did not signifi cantly affect the UPF value of the fabric, but it did influence the morphology of the synthesised nanoparticles. With a longer drying time the nanoparticles were more rounded. The samples had poor wash fastness even after the fi rst wash, which was found through low UPF values.

The influence of the treatment process on the dyeability of cotton fabric with a natural dye from goldenrod blooms was studied in this research. The dyeing was performed on untreated and treated cotton samples. The treating of the samples, using mordant (KAl(SO4)2 × 12 H2O), was performed before and during the dyeing process, whilst treatment with a cationic agent (Denimcol FIX-OS) was performed only before dyeing. The dyeing was carried out at 60 °C in two repetitions in three different concentrations of goldenrod aqueous extract, namely without dilution, and by diluting the extract with distilled water at volume ratios of 1:2 and 1:3. Spectrophotometric measurements were done before and after 1, 5, and 10 washing cycles. Colour fastness to rubbing was visually evaluated using a grey scale. Colour fastness to artificial light was visually evaluated using a blue scale, as well as spectrophotometrically before and after illumination of the dyed samples. The results of the research show that the cationic treatment of cotton fabric essentially influences on higher dye uptake in comparison to treatment using mordant before or during dyeing. Cotton samples that are treated with a cationic agent have the highest colour fastness to washing, rubbing, and light among all of the studied samples.

This paper presents an in-depth study of the surface modification of polyethylene terephthalate fabric (PET) with non-thermal plasma and temperature- and pH-responsive nanogel (PNCS) to impart smart thermoregulation properties. To increase the adsorption of the PNCS nanogel onto the PET, ammonia and oxygen plasma and a combination of both plasma gases were used. Chemical changes caused by the plasma treatment were investigated using X-ray photoelectron spectroscopy (XPS), morphological changes were determined using scanning electron microscopy (SEM) and the swelling and de-swelling ability was determined by measuring the moisture content at 20 and 40 °C. The greatest deposition of the PNCS nanogel, with unimpaired swelling ability, was found on the oxygen-plasma-treated samples, as they had the highest O/C ratio. Meanwhile, the least promising results were found for the samples treated with a combination of oxygen and ammonia plasma, where the highest concentration of nitrogen was present on the fibre surface. Since the treatment with oxygen plasma proved to be the most effective method, different exposure times to the oxygen plasma, namely, 10, 30 and 60 s, were studied in the second part of this study. The optimal oxygen plasma treatment time was found to be 30 s, where the greatest deposition and unhindered swelling/de-swelling ability of the PNCS nanogel on the PET fabric was achieved.

A new functional, stimuli-responsive microgel coating on polyamide 6 (PA6) fabric with simultaneous temperature (T)- and pH-responsive moisture management, UV protection and photocatalytic self-cleaning properties was prepared by applying poly-(N-isopropylacrylamide)/chitosan (PNCS) microgel in combination with ZnO nanoparticles to PA6 fabric. Two different application procedures were used: (i) the application of PNCS previously functionalized with a ZnO nanoparticles suspension and (ii) the application of PNCS with the subsequent application of a ZnO nanoparticles suspension. The coatings were fabricated on the untreated PA6 fabric as well as on fabric previously modified by the silica matrix created by the sol-gel precursor iSys MTX in order to increase the adsorption ability and uniformity of the coating. The chemical and morphological properties of the coated PA6 samples were determined by SEM and FTIR analyses. Stimuli responsiveness and functional properties were assessed by the moisture content, water vapour transmission rate, water uptake, UV protection and photocatalytic self-cleaning measurements. The results show that the application procedure as well as the pretreatment of PA6 fabric greatly infl uenced the properties of the coating. Accordingly, the most appropriate procedure included the creation of a silica matrix on the PA6 fibres followed by the application of PNCS and subsequent application of ZnO. In this case, the modified PA6 fabric exhibited high T and pH responsiveness due to the swelling/de-swelling activity of the PNCS microgel, as well as good UV protection with UPF equal to 18.8 and photocatalytic self-cleaning properties that are even higher than those in the case of the one-component coating with ZnO.

This work presents the novel and entirely green in situ synthesis of zinc oxide nanoparticles (ZnO-NP) on cotton fabric. Pomegranate peel extract was used as a reducing agent and wood ash extract was used as an alkali source for the formation of ZnO-NP from zinc acetate. Four different synthesis methods, which varied in drying between immersion of fabric in the active solutions for synthesis and the use of padding and ultrasonication, were investigated to evaluate the most suitable one to achieve excellent ultraviolet (UV) protective properties of the functionalized textile. For comparison, the cotton fabrics were also functionalized with each active solution separately or in a combination of two (i.e., Zn-acetate and plant extract). Scanning electron microscopy (SEM), inductively coupled plasma mass spectroscopy (ICP-MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) analysis, and atomic force microscopy (AFM) confirm the successful formation of ZnO-NP on cotton. Among the synthesis methods, the method that included continuous drying of the samples between immersion in the active solutions for synthesis (Method 4) was found to be the most suitable to deliver uniformly impregnated cotton fibers with numerous small ZnO wurtzite structured crystals and excellent UV protection, with a UV protection factor of 154.0. This research presents an example of a green circular economy where a bio-waste material can be used to produce ZnO-NP directly on cotton at low temperatures and short treatment times without the addition of chemicals and enables the production of cellulosic fabrics with excellent UV protection.

Polyethylene terephthalate (PET) fabric was treated in a late afterglow of plasma created by a microwave (MW) discharge in the surfatron mode, by using oxygen (O2) and ammonia (NH3) gases. The series of treatments using one gas or the combination of both at different treatment times were performed in order to increase the embedment of UV-responsive microcapsules that were deposited onto PET with pad-dry-cure process. Plasma in both gases was characterized by optical emission spectroscopy (OES), which showed substantial dissociation of O2 and NH3 molecules as well as formation of NHx radicals due to the partial dissociation of ammonia molecules. The chemically active species in the plasma afterglow changed the surface properties of PET that were analysed using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF–SIMS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and water absorption analysis. The effectiveness of plasma treatment on embedment of UV-responsive microcapsules on PET was evaluated by UV-responsiveness, colour strength and colour depth using reflectance spectroscopy, add-on and air permeability, respectively. Treating PET by O2 afterglow followed by a longer treatment by NH3 afterglow increased the polymers hydrophilicity and concentration of nitrogen-rich functional groups on surface that enabled higher uptake of UV-responsive microcapsules, and consequently better responsiveness of fabric to UV radiation. The add-on of microcapsules was almost 8-times higher and the colour depth increased up to 75% for plasma treated samples.

The aim of this research was to study the possibility of introducing a three-stage procedure for chemical modifi cation of textile fi bres to achieve antimicrobial properties as well as to determine the infl uence of the procedure on chemical, morphological and functional properties of fi bres and their degree of biodegradation.The procedure was applied to 100% cotton (CO) and 100% polyester (PES) fabrics and a CO/PES fabric blend with a ratio of 50%/50%. The procedure of chemical modifi cation included (i) pre-treatment of fi bres with oxygen plasma, (ii) application of organofunctional trialkoxysilane for the creation of a silica matrix, and (iii) in situ synthesis of silver chloride. For comparison, a silica matrix with incorporated silver nanoparticles was also created on the samples without plasma treatment. Untreated and chemically modifi ed samples were buried in soil for a defi ned period of time, and biodegradation of the fi bres was conducted. Chemical and morphological changes after chemical modifi cation and biodegradation were determined by microscopic and spectroscopic analyses, thin-layer wicking, and colour measurements. The results show that chemical modifi cation did not cause signifi cant morphological changes to the fi bres. Treatment with oxygen plasma increased the fi bre hydrophilicity, which resulted in an increased concentration of adsorbed silver. The presence of silver on the CO and CO/PES fabrics signifi cantly decreased the degree of biodegradation compared to the untreated samples. Plasma treatment increased the degree of fi bre biodegradation irrespective of the silver concentration present on the fi bres. The low degree of biodegradation of the PES fabric was more due to the high hydrophobicity and crystallinity of the fi bres than to the presence of silver.

Dyeing with natural dyes extracted from curcuma, green tea, avocado seed, pomegranate peel and horse chestnut bark was studied to evaluate the dyeability and ultraviolet (UV) blocking properties of raw and bleached/mercerised cotton fabrics. 20 g/l of powdered plant material was extracted in distilled water and used as a dyeing bath. No mordants were used to obtain ecologically friendly finishing. The colour of samples was measured on a refl ectance spectrophotometer, while UV-blocking properties were analysed with UV-Vis spectrophotometer. The results showed that dyeing increased UV protection factor (UPF) to all samples, however much higher UPF values were measured for the dyed raw cotton samples. The highest UPF values were obtained on both cotton fabrics dyed with pomegranate peel and green tea extracts, giving them excellent protective properties (UPF 50+). The lowest UPF values were obtained by dyeing cotton with avocado seed extract and curcumin. Dyeing with selected dyes is not stable to washing, so the UV-blocking properties worsen after repetitive washing. However, raw cotton samples retain their very good Uvblocking properties, while bleached/mercerised cotton fabrics do not provide even satisfactory UV-blocking properties. No correlation between CIE L*a*b*, K/S and UPF values were found.

Dyeing of raw and bleached cotton fabrics with a natural dye of curcumin was studied to implement the ancient and environmentally friendly technique of developing photos called anthotype. With the aim of achieving diff erent colours of dyed cotton fabrics, several modifi cations were performed, such as extraction of curcumin in hard and soft water, after-treatments of dyed cotton, i.e. with ferrous sulphate, zinc chloride and silver nitrate, aftertreatment in alkaline bath, and aftertreatment with other natural dyes (blueberry and raspberry). The colour values of dyed samples were determined using a refl ectance spectrophotometer. Colour stability to light was determined by the standard method in Xenotest. It was found that the use of various metal salts, natural dyes, alkalinity and hardness of water infl uenced the colour changes of the substrate. Yellow, red, greenish and brownish colours of fabrics were produced by diff erent treatments. Since the use of metal ions improved the stability of curcumin to light, the motifs produced by anthotype technique were hardly visible. It was found that the natural dye of blueberries and raspberries did not infl uence the light stability, therefore a larger colour contrast between exposed and unexposed areas of the fabric was visible, and consequently good visibility of the motifs was achieved.

The high-performance fibrous polymers are incorporated in products for specific uses where have to perform exceptionally (i.e. high strength, stiffness, heat resistance and/or chemical resistance). The lack of certain functional groups and high crystallinity of high-performance fibrous polymers decrease their adhesion when used in a matrix. One of the most promising and environmentally benign methods to overcome these the drawbacks is plasma technology. The chapter reviews the contemporary research on the topic. The plasma surface modifications, such as cleaning, physical etching, chemical modification, and polymerization on glass, aramid, carbon, polyethylene and poly(p-phenylene benzobisoxazole) fibrous polymers are discussed.

Oxygen plasma pre-treatment was applied to cotton fabric with the aim of improving the water repellency performance of an inorganic-organic hybrid sol-gel perfluoroalkyl-functionalized polysilsesquioxane coating. Cotton fabric was pre-treated with low-pressure oxygen plasma for different treatment times and operating powers. Afterward, 1H,1H,2H,2H-perfluorooctyltriethoxysilane (SiF) was applied to the cotton fabric samples using the pad-dry-cure method. The surfaces of the untreated and modified cotton fibers were characterised using Fourier transform infrared spectroscopy, Xray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water repellency of the SiF-coated fabric samples was evaluated using static and sliding contact angle measurements with water. The results show that the plasma treatment with the shortest treatment time (10 s) and the lowest operating current (0.3 A) increased the atomic oxygen/carbon ratio of the cotton fiber surface from 0.6 to 0.8 and induced the formation of a nano-sized grainy surface. Increasing the plasma treatment time and/or operating current did not intensify the surface changes of the cotton fibers. Such saturation effects were explained by the large influence of reactive oxygen atoms during the plasma treatment. The measured static water contact angles on the surface of the untreated and plasma pre-treated and SiF-coated cotton fabrics showed that the oxygen plasma pre-treatment enabled the increase of the water contact angle from 135° to ≈150°, regardless of the applied plasma treatment time and discharge power. This improvement in the hydrophobicity of the SiF coating was followed by a decrease in the sliding angle of water droplets by more than 10° compared to the plasma untreated and SiF-coated sample characterized by a water sliding angle of 45°. Additionally, measurements of the water sliding angle revealed that the increase of the static contact angle from 149° to 150° corresponded to a drop of the water sliding angle from 33 to 24°, which suggests that the plasma pre-treatment of 20 s at an operating current of 0.3 A produced the best water-repellent performance of the SiF-coated cotton fabric.

To achieve colourful and antibacterial textiles using ecologically friendly processes, cotton and bamboo rayon knitted fabrics were treated using radio-frequency low-pressure water vapour plasma and dyed with the extract of Fallopia japonica (Japanese knotweed) rhizome. Optical emission spectroscopy (OES) was used to observe plasma during the sample treatment and scanning electron microscopy (SEM) to study morphological changes of samples. The adsorption of F. japonica on cellulose substrates was studied by measuring the colour (CIE L*a*b*) and colour yield (K/S) of dyed samples. The antibacterial properties against Escherichia coli and Staphylococcus aureus were tested as well. The results show that water vapour plasma induces weak etching effect on the surface of the cellulose samples, since water molecules in plasma dissociate to produce hydroxyl radicals and oxygen atoms. Plasma-treated samples had higher dye uptake, and better antibacterial properties against S. aureus. The samples did not have antibacterial properties against E. coli.

The cellulose fabrics made from 100 % cotton with antibacterial and UV protective properties were successfully created by loading of Ag/TiO2 nanocomposite during and after dyeing with yellow, red and blue reactive dye. Blank dyeing (dyeing with all chemicals except dye) was performed to show that reactive dyes have an ability to increase the adsorption and adhesion of Ag/TiO2 nanocomposite on cotton fabrics. The colour of the samples before and after washing and exposure to artificial light was measured by reflectance spectroscopy. The presence of nanocomposite on samples was confirmed by scanning electron microscope. The increased adsorption capacity of cotton towards Ag/TiO2 nanocomposite due to the presence of reactive dyes was confirmed by measuring the quantity of silver using inductively coupled plasma mass spectroscopy. The same samples showed excellent UV protective properties with UV protection factor (UPF 50+), and excellent antibacterial properties against E. coli and S. aureus. Due to a good adhesion of nanocomposite on samples where loading of nanocomposite and dyeing with reactive dye was performed simultaneously, the samples retained their excellent protective properties after repetitive washing cycles.

The development of lignocellulosic natural-fibre-reinforced polymers composites are constrained by two limitations: the upper temperature at which the fibre can be processed and the significant differences between the surface energy of the fibre and the polymer matrix. Since the fibres and matrices are chemically different, strong adhesion at their interface is needed for the effective transfer of stress and bond distribution throughout the interface. The present study investigated the plasma induced effects on the surface properties of natural coir fibres. Weakly ionized oxygen plasma was created in two different discharge chambers by an inductively coupled radiofrequency (RF) discharge. The water absorption studies showed an increase of water sorption from 39% to 100%. The morphological study using scanning electron microscopy (SEM) analysis also confirmed the surface changes which were observed after the plasma treatment. The topographic measurements and phase imaging done using atomic force microscopy (AFM) indicated difference in topographic features and etching of coir wall, which points to the removal of the first layer of coir fibre. X-ray photoelectron spectroscopy (XPS) analysis revealed that the oxygen content measured for samples treated at 50 Pa increased from initial 18% to about 32%.

Raw cotton fabrics have been exposed to low-pressure non-equilibrium gaseous plasma to improve the adsorption of natural dyes as well as ultraviolet (UV) protection factor. Plasma created in a glass tube by an electrodeless radiofrequency (RF) discharge was created either in oxygen or ammonia at the pressure of 50 Pa to stimulate formation of oxygen and nitrogen groups, respectively. The type and concentration of functional groups was determined by X-ray photoelectron spectroscopy (XPS) and morphological modifications by scanning electron microscopy (SEM). The colour yield for curcumin dye was improved significantly for samples treated with ammonia plasma what was explained by bonding of the dye to surface of amino groups. Contrary, the yield decreased when oxygen plasma treatment was applied due to the negatively charged surface that repels the negatively charged dye molecules. The effect was even more pronounced when using green tea extract as the colouring agent. The colour difference between the untreated and ammonia plasma treated sample increased linearly with plasma treatment time reaching the factor of 3.5 for treatment time of 300 s. The ultraviolet protection factor (UPF) was over 50 indicating excellent protection due to improved adsorption of the dye on the ammonia plasma treated samples.

Low-pressure oxygen plasma created by an electrodeless radiofrequency (RF) discharge was applied to modify the properties of cellulosic fibrous polymer (cotton) in order to improve adsorption properties towards zinc oxide (ZnO) nanoparticles and to achieve excellent ultraviolet (UV) protective properties of cotton fabric. The chemical and physical surface modifications of plasma-treated cotton fabric were examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The mechanical properties of plasma-treated samples were evaluated, measuring strength and elongation of the fabrics. The quantity of zinc on the ZnO-functionalized cotton samples was determined using inductively coupled plasma mass spectrometry (ICP-MS) and the effectiveness of plasma treatment for UV protective properties of cotton fabrics was evaluated using UV-VIS spectrometry, measuring the UV protection factor (UPF). The results indicated that longer plasma treatment times cause higher concentration of oxygen functional groups on the surface of fibres and higher surface roughness of fibres. These two conditions are crucial in increasing the content of ZnO nanoparticles on the fibres, providing excellent UV protective properties of treated cotton, with UPF factor up to 65.93.