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© 2021 Elsevier B.V.TlGaS2 layered single crystals have been an attractive research interest due to their convertible characteristics into 2D structure. In the present paper, structural, optical and thermoluminescence properties of TlGaS2 single crystals were investigated. XRD pattern of the crystal presented five well-defined peaks associated with monoclinic unit cell. Band gap and Urbach energies were found to be 2.57 and 0.25 eV, respectively, from the analyses of transmittance spectrum. Thermoluminescence measurements were carried out above room temperature up to 660 K at various heating rates. One TL peak with peak maximum temperature of 573 K was obtained in the TL spectrum at 1.0 K/s. Curve fitting, initial rise and variable heating rate methods were used for analyses. All of those resulted in presence of a deep trapping level with activation energy around 0.92 eV. Heating rate dependence of the TL peak was also studied and it was indicated that peak maximum temperature shifted to higher temperatures besides decreasing TL intensity as the higher heating rates were employed.

© 2022 Elsevier B.V.The present paper reports the structural and optical properties of thermally evaporated TlGaSe2 thin films. X-ray diffraction pattern of evaporated film presented two diffraction peaks around 24.15 and 36.00° which are associated with planes of monoclinic unit cell. Surface morphology of the TlGaSe2 thin films was investigated by scanning electron and atomic force microscopy techniques. Although there was observed some ignorable amount of clusters of quasi-spherical shape in the scanning electron microscope image, the film surface was observed almost uniform. Raman spectrum exhibited six peaks around 253, 356, 488, 800, 1053 and 1440 cm−1 associated with possible vibrational mode combinations. Band gap energy of the thin film was determined as 3.01 eV from the analyses of transmission spectrum. Transmission spectrum presented strong Urbach tail and analyses of corresponding region resulted in Urbach energy of 0.66 eV. The structural and optical properties of deposited TlGaSe2 thin films were compared with those of single crystal. This comparison would provide valuable information about influence of thickness on the studied compounds.

Bi12SiO20 (BSO) single crystal belongs to the sillenite semiconducting family known as defective compounds. The present paper investigates the defect centers in BSO grown by Czochralski method by means of thermally stimulated current (TSC) measurements performed in the 10–260 K range. The TSC glow curve obtained at heating rate of β = 0.1 K s−1 presented several peaks associated with intrinsic defect centers. The activation energies of defect centers were revealed as 0.09, 0.15, 0.18, 0.22, 0.34, 0.70 and 0.82 eV accomplishing the curve fit analyses method. The peak maximum temperatures and orders of kinetics of each deconvoluted peak were also determined as an outcome of fitting process. TSC experiments were expanded by making the measurements at various heating rates between 0.1 and 0.3 K s−1 to get information about the heating rate dependent peak parameters.

Interfacial layers play a critical role in building up the Ohmic contact between electrodes and functional layers in organic photovoltaic (OPV) solar cells. These layers are based on either inorganic oxides (ZnO and TiO2) or water-soluble organic polymers such as poly[(9,9-dioctyl-2,7-fluorene)-alt-(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)] and polyethylenimine ethoxylated (PEIE). In this work, we have developed a series of novel poly(ionic liquid) nonconjugated block copolymers for improving the performance of inverted OPV cells by using them as work function modifiers of the indium tin oxide (ITO) cathode. Four nonconjugated polyelectrolytes (n-CPEs) based on polystyrene and imidazolium poly(ionic liquid) (PSImCl) were synthesized by reversible addition–fragmentation chain transfer polymerization. The ratio of hydrophobic/hydrophilic block copolymers was varied depending on the ratio of polystyrene to the PSImCl block. The ionic density, which controls the work function of the electrode by fo...

This paper presents the work carried out within the European project RENAISSANCE-ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications. Within the project different types of innovative polyelectrolytes were synthesized such as poly(ionic liquid)s coming from renewable or natural ions, thiazolium cations, catechol functionalities or from a new generation of cheap deep eutectic monomers. Further, macromolecular architectures such as new poly(ionic liquid) block copolymers and new (semi)conducting polymer/polyelectrolyte complexes were also developed. As the final goal, the application of these innovative polymers in energy and the environment was investigated. Important advances in energy storage technologies included the development of new carbonaceous materials, new lignin/conducting polymer biopolymer electrodes, new iongels and single-ion conducting polymer electrolytes for supercapacitors and batteries and new poly(ionic liquid) binders for batteries. On the other hand, the use of innovative polyelectrolytes in sustainable environmental technologies led to the development of new liquid and dry water, new materials for water cleaning technologies such as flocculants, oil absorbers, new recyclable organocatalyst platforms and new multifunctional polymer coatings with antifouling and antimicrobial properties. All in all this paper demonstrates the potential of poly(ionic liquid)s for high-value applications in energy and enviromental areas. © 2017 Society of Chemical Industry

New polymeric materials such as polymer electrolytes or redox polymers are actively being searched for in order to increase the performance and security of electrochemical energy storage devices such as batteries. Poly(ionic liquid)s are very popular materials in energy nowadays finding applications as ion conducting polymer electrolytes and electrode binders for batteries and supercapacitors. In this work, the incorporation of redox-active counter anions (anthraquinone and nitroxide molecules) into poly(ionic liquid)s has broadened the scope of applications as redox-active materials in different energy storage technologies. Polymers having those known redox-active molecules usually involve challenging synthetic routes and yield insoluble materials very difficult to handle. In this paper, we show that the synthesis of the redox-active poly(ionic liquid)s can be achieved through a straightforward and simple anion exchange reaction. We also show that this new family of redox-active poly(ionic liquid)s can be applied in several electrochemical energy storage technologies such as lithium batteries, as electrocatalysts in fuel cells and metal–air batteries or as electrolytes in organic redox flow batteries.

Biomaterials must fulfill some requirements before moving into in vivo application. In vitro test is usually conducted as a preliminary screening evaluation. Although most of the studies are focused in the cytotoxicity, interactions between blood elements and the biomaterials or hemocompatibility must also be considered. Aliphatic polyurethanes have been always considered ideal candidates for in-vivo application due to their versatility. However, the utilization of metal catalyst to promote the polymerization have limited their use. Recently, some organocatalysts have shown to be competitive to tin based catalyst for the preparation of polyurethanes and have relaunched their use in biomedicine. In the present study we carried out the organocatalyzed polymerization of 5 commercially available isocyanates, hexamethylene diisocyanate, isophorone diisocyanate, trans -1,4-cyclohexylene diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate) and l -lysine diisocyanate to analyze the cytotoxicity and hemocompatibility of the resultant polymers as a function of the employed diisocyanate. The diisocyanates were polymerized with hydroxy end-capped oligomeric poly (tetramethylene glycol) (PT2K) as the long chain diol and 1,3-propanediol as the short chain diol. We demonstrated that from selected diisocyanates, lysine diisocyanate based polyurethanes possessed lower cytotoxicity and better hemocompatibility than the other polyurethanes. In comparison with a well known blood compatible polymer such as poly(2-methoxyethyl acrylate), the lysine diisocyanate based polyurethanes showed remarkable values in terms of cytotoxicity and platelet adhesion, but major levels of protein adsorption.

Non-viral gene delivery vectors have emerged as potential alternatives in the field of gene therapy by replacing the biological viral vectors. DNA–cationic polymer complexes are one of the most promising systems to target many inborn or acquired diseases without the utilization of conventional drugs. Despite the excellent binding efficiency of cationic polymers, the gene transfection seems limited to date. In this work, a series of ammonium-based block-copolymers with different alkyl side chains (ethyl, butyl, and hexyl) and functionality (alcohol, amine, and alkyl) have been prepared to evaluate their capacity to deliver genetic material. First, different ionic liquid monomers with different pendent functional groups were prepared and characterized. Then, polyplexes elaborated with different polymers at several polymer DNA ratios (w/w) were characterized in terms of size, zeta potential, and DNA binding, release, and protection capacity. Finally, the transfection efficiency and cell viability was evaluated in ARPE19 cells. We found that only the systems containing the amine pendent group were able to transfect ARPE19 cell and, that this amine containing polymer was less cytotoxic even at high polymer/DNA ratios (30:1). In conclusion, our studies suggested that the proper selection of the pendent group substantially impacts overall transfection efficiency of cationic polymers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016

The design of high performance solid sorbent materials for CO2 capture is a technology which has been employed to mitigate global warming. However, the covalent incorporation of functionalities into polymeric supports usually involves multistep energy-intensive chemical processes. This fact makes the net CO2 balance of the materials negative even though they possess good properties as CO2 sorbents. Here we show a new family of polymers which are based on amines, amidoximes, and natural carboxylic acids and can be obtained using sustainable low energy processes. Thus, deep eutectic monomers based on natural carboxylic acids, amidoximes, and amines have been prepared by just mixing with cholinium type methacrylic ammonium monomer. The formation of deep eutectic monomers was confirmed by differential scanning calorimetry measurements. In all cases, the monomers displayed glass transition temperatures well below room temperature. Computational studies revealed that the formation of eutectic complexes lengthen...

The incorporation of ionic liquid (IL) chemistry into functional polymers has extended the properties and applications of polyelectrolytes. However, ILs are expensive due to the presence of fluorinated anions or complicated synthetic steps which limit their technological viability. Here, we show a new family of poly(ionic liquid)s (PILs) which are based in cheap and renewable chemicals and involves facile synthetic approaches. Thus, deep eutectic monomers (DEMs) are prepared for the first time by using quaternary ammonium compounds and various hydrogen bond donors such as citric acid, terephthalic acid or an amidoxime. The deep eutectic formation is made through a simple mixing of the ingredients. Differential scanning calorimetry, nuclear magnetic resonance (NMR) and computational studies reveal the formation of the DEMs due to the ionic interactions. The resulting DEMs are liquid which facilitates their polymerization using mild photopolymerization or polycondensation strategies. Spectroscopic characterizations reveal the successful formation of the polymers. By this way, a new family of PILs can be synthesized which can be used for different applications. As an example, the polymers show promising performance as solid CO2 sorbents. Altogether the deep eutectic monomer route can lead to non-toxic, cheap and easy-to-prepare alternatives to current PILs for different applications.

New methods for preparing polymeric nanoparticles are actively being investigated such as self-assembly of amphiphilic block copolymers, self-crosslinking of single-chain macromolecules, nanoprecipitation or emulsion–miniemulsion polymerizations. However, most methods require multi-step synthesis, controlled polymerization mechanisms and tedious purification processes. In this work, amphiphilic poly(ionic liquid) random copolymers that self-assemble into polymeric nanoparticles were prepared in water through a simple partial anion exchange process. This method was demonstrated for different cationic polyelectrolytes such as poly(1-vinyl-3-ethyl imidazolium bromide), poly(diallyldimethylammonium chloride) and poly(allylamine hydrochloride). Their partial anion exchange was conducted by the addition of lithium bis(trifluoromethanesulphonyl)imide to the aqueous solution of the polymer. It was found out that the amphiphilic poly(ionic liquid)s containing small amounts (1–10%) of bis(trifluoromethanesulfonimide) anion self-assemble into spherical nanoparticles as revealed by dynamic light scattering and transmission electron microscopy. The nanoparticle size ranged from 100 nm to 600 nm depending on the extent of partial anion exchange and the nature of the polyelectrolyte. As an application, the poly(ionic liquid) nanoparticles were used as flocculants for water purification. The use of amphiphilic poly(ionic liquid)s as flocculants enhanced the evolution rate of the sediment considerably in comparison with the parent polyelectrolytes.

Poly(e-caprolactone)–polydimethylsiloxane–poly(e-caprolactone) (PCL-PDMS-PCL) triblock copolymers with a wide range of block lengths (1000–32,000 g/mol) were synthesized by the ring-opening polymerization of e-caprolactone using aminopropyl terminated PDMS oligomers as the initiator. Reactions were carried out in bulk or solution at 125 ± 5 °C under the catalytic action of tin octoate. Products obtained in high yields were characterized by FTIR spectroscopy, gel permeation chromatography, X-ray diffraction, temperature-dependent optical microscopy, differential scanning calorimetry, atomic force microscopy, scanning electron microscopy and static water contact angle measurements. Effect of the polymer composition and the molecular weight of the PDMS and PCL blocks on; (i) copolymer morphology and the extent of microphase separation, (ii) crystallization of PCL segments and (iii) surface properties of copolymers were investigated. Regardless of the block lengths, all PCL-PDMS-PCL copolymers displayed well microphase separated morphologies. The extent of microphase separation, resultant morphology and sizes of the microphases were strongly dependent on the copolymer composition and the block lengths of both PCL and PDMS segments. Crystalline PCL microphase was observed in all copolymers, which increased as a function of PCL content and molecular weight. Hydrophobicity of the copolymer surfaces was improved with increasing PDMS molecular weight, as determined by static water contact angle measurements.

Polymeric ionic liquids have been attracting increasing interest as proton exchange membranes for anhydrous fuel cell applications. In this work, novel and designed composite membranes based on the polymeric ionic liquid matrix poly([HSO3-BVIm][TfO]) and its analogue non-polymerizable ionic liquid [HSO3-BMIm][TfO] are developed for H2/O2 proton exchange membrane fuel cells working without external humidification. The chemical affinity between the ionic liquid monomer and the ionic liquid results in stable, flexible and transparent polymeric membranes. The effect of temperature and the quantity of non-polymerizable ionic liquid on the ionic conductivity and fuel cell performance are analyzed. Fuel cell tests and ionic conductivity experiments show the great potential of these ionic liquid-based polymers as proton exchange membranes.

International audience; The organometallic-mediated radical polymerization (OMRP) of N-vinyl-3-alkylimidazolium-type monomers, featuring the bis(trifluoromethylsulfonyl)imide counter-anion (Tf2N-) in the presence of Co(acac)(2) as controlling agent, is reported. Polymerizations of monomers with methyl, ethyl, and butyl substituents are fast, reaching high monomer conversion in ethyl acetate as solvent at 30 degrees C, and afford structurally well-defined hydrophobic poly(ionic liquid)s (PILs) of N-vinyl type. Block copolymer synthesis is also achieved by sequential OMRP of N-vinyl-3-alkyldazolium salts carrying different alkyl chains and different counteranions (Tf2N- or Br-). These block copolymerizations are carried out at 30 degrees C, either under homogeneous solution in methanol or in a biphasic medium consisting of a mixture of ethyl acetate and water. Unprecedented PIL-b-PIL block copolymers are thus prepared under these conditions. However, anion exchange occurs at the early stage of the growth of the second block. Finally, diblock copolymers generated in the biphasic medium can be readily coupled by addition of isoprene, forming all PIL-based and symmetrical ABA-type triblock copolymers in a one-pot process. Such a direct block copolymerization method, involving vinylimidazolium monomers bearing different alkyl chains, thus opens new opportunities in the precision synthesis of all PIL-based block copolymers of tunable properties.

Bu araştırmanın amacı, sosyal medya mecralarından birisi olan Facebook'un reklamcılık sektöründeki yeri ve önemini ortaya koymaktır. Dolayısıyla Facebook'ta verilen reklamların Facebook kullanıcılarının satın alma öncesi ve sonrası davranışlarına olan etkilerini tespit edip, bu tespitler sonucunda markaların satışlarını artırmasına yönelik öneriler sunmaktır. Araştırma, Konya ilinde yaşayan 271 kişi üzerinde yapılmıştır. Bu kişiler belirlenirken rastlantısallık dikkate anket gerçekleştirilmiştir. Araştırmada hem nicel hem nitel araştırma yöntemlerinden yararlanılmış ve genel tarama yöntemi olarak anket uygulaması kullanılmıştır. Araştırmada veriler; kişilerin demografik özellikleriyle Facebook kullanıcılarının satın alma öncesi ve sonrası davranışlarına yönelik sorular ile elde edilmiştir. Araştırma sonucunda, Facebook kullanıcılarının gördükleri reklamlardan etkilenip bir ürünü satın alma öncesi ve sonrası davranışlarına yönelik her bir soru tartışılmış ve sonuçlar elde edilmiştir. Elde edilen bu sonuçlara göre markaların satışlarını artırmasına yönelik önerilerde bulunulmuştur., The purpose of this research is to reveal the importance and the place of Facebook, one of the social media channels, in the advertising industry. Therefore, it is to detect the effects of the Facebook ads on Facebook users' pre and post purchase behaviors, and to offer suggestions for increasing the sales of the brands as a result of these determinations. The study was conducted on 271 people living in Konya. When these persons were identified, the randomness taking into account. Both quantitative and qualitative research methods were used in the research and questionnaire application was used as the general screening method. Datas in the research; obtained with questions about the behavior of Facebook users before and after purchasing with demographic characteristics of the users. As a result of the research, each question about the pre- and post-purchase behaviors of a product affected by the ads seen by Facebook users were obtained. According to these results, suggestions have been made to increase sales of brands

Aqueous biphasic systems (ABSs) provide a sustainable and efficient alternative to conventional liquid-liquid extraction techniques with volatile organic solvents, and can be used for the extraction, recovery, and purification of diverse solutes. In this work, and for the first time, ABSs composed of poly(ionic liquid)s (PILs) and inorganic salts were measured at 25 °C and atmospheric pressure. New PILs having pyrrolidinium polycations combined with different counter-anions, namely acetate [Ac](-), trifluoroacetate [TFAc](-), hexanoate [Hex](-), adipate [Adi](-), and citrate [Cit](-) were synthesized, by a simple and environmentally-friendly procedure, and characterized. The effect of the PIL features, namely molecular weight and anionic character, and other experimental variables, such as temperature, on the phase splitting ability was researched. The aptitude of the studied ABS to be implemented as separation technologies was also evaluated through the use of a model biomolecule, tryptophan.

Cholinium-based bio-ion gels were prepared by photopolymerization of poly(cholinium lactate methacrylate) network within cholinium lactate ionic liquid. The rheological and thermal properties as well as ionic conductivity of ion gels of different compositions were measured. As indicated by rheological measurements, the ion gels show the properties of gel materials which become soft by increasing the amount of free ionic liquid. Cholinium ion gels with various composition of free ionic liquid vs. methacrylic network show glass transitions between −40° and −70 °C and thermal stability up to 200 °C. The ionic conductivity of these gels increases from 10−8 to 10−3 S cm−1 at 20 °C by varying the amount of free ionic liquid between 0 and 60 wt%, respectively. Low glass transition temperature and enhanced ionic conductivity make the cholinium-based ion gels good candidates to be used as a solid electrolytic interface between the skin and an electrode. The ion gels decrease the impedance with the human skin to levels that are similar to commercial Ag/AgCl electrodes. Accurate physiologic signals such as electrocardiography (ECG) were recorded with ion gels assisted electrodes for a long period of time (up to 72 h) with a remarkable stability. The low toxicity and superior ambient stability of cholinium ionic liquids and ion gels make these materials highly attractive for long-term cutaneous electrophysiology and other biomedical applications.

Proton conducting polymeric membranes are highly searched in many different technologies ranging from energy to biosensing. Protic ionic liquids and their polymeric version represent a new family of proton conducting molecules with relatively facile synthesis and excellent properties. In this work, protic poly(ionic liquids) having the most popular phosphonium counter-cations are presented for the first time. The synthesis is carried out through proton transfer reactions or through ion exchange reactions by using commercially available tertiary phosphines. Tributyl-, trioctyl-, and tricyclohexyl-phosphine are selected to form the desired cations. Polystyrene sulfonic acid, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), and lithium poly[(4-styrenesulfonyl) (trifluoromethanesulfonyl)imide] polymers are used to form the polymeric anions. The chemical structure of the protic poly(ionic liquids) is confirmed by spectroscopic characterizations such as Fourier transform infrared and nuclear magnetic resonance spectroscopies. Thermal properties of the polymer are characterized by means of differential scanning calorimetry and thermogravimetric analysis. Polymers exhibit good membrane forming ability as well as high ionic conductivities in the range of 10-8 to 10-3 S cm-1 from 30 to 90 °C.

Summary Cholinium, a quaternary ammonium cation, trimethylethanol ammonium, is an essential micronutrient which supports several biological functions. In this work, a new cholinium based ionic liquid methacrylate monomer was used to process cellulose and produce optically transparent coatings through a simple photopolymerization procedure. The same monomer was also employed to manufacture biocompatible ion gels. Simply, the methacrylic monomer was photopolymerized within the ionic liquid matrix to form a gel type material.

New polylactide-block-poly(2-cholinium lactate methacrylate) amphiphilic block copolymers were synthesized and characterized. These new block copolymers are composed of chemicals from renewable sources such as lactic acid and cholinium. First a polylactide macro chain transfer agent was synthesized and used to conduct block copolymerization of 2-cholinium lactate methacrylate ionic liquid monomer to form an amphiphilic block copolymer. The polymerizations were successfully conducted through ring-opening polymerization and controlled radical RAFT techniques and confirmed by 1H NMR and GPC experiments. DLS experiments revealed the formation of self assembled micelles in water and TEM studies confirmed the presence of spherical nanostructures in a dry state having sizes down to 17 nm. To the best of our knowledge this is the first example of an amphiphilic block copolymer having lactic acid units in both copolymer blocks of potential interest in nanomedicine.

Hydrophilization of polydimethylsiloxane–urea copolymer (PSU) surfaces and the extent of hydrophobic recovery were investigated as a function of; (i) UV/ozone (UV/O) exposure time, (ii) the aging period after UV/O exposure, (iii) sample preparation method, and (iv) polydimethylsiloxane (PDMS) soft segment molecular weight of the copolymer (1500, 3000 and 11,000 g/mol). All copolymers had a constant urea hard segment content of 15% by weight. Samples were prepared by three different methods, which were; solution casting, spin-coating and electrospinning. XPS spectra clearly showed transformation of PDMS into SiO 2 and sub-oxides, which increased gradually with increasing UV/O exposure time. XPS and ATR-FTIR measurements also revealed that the copolymer based on PDMS-11000 displayed the highest amount of SiO 2 formation and overall surface modification. Static water contact angle values of the spincoated silicone–urea copolymer films decreased significantly from 110° to 43° after 3 h of UV/O exposure. Interestingly, the hydrophobicity of the electrospun fibers was retained under similar UV/O exposure conditions, most probably due to the preserved surface roughness. Hydrophobic recovery was evaluated after 2 months of storage at ambient conditions. The slowest recovery was observed for spin-coated copolymer film based on PDMS-11000, due to higher amount of surface oxidation and formation of a thicker SiO 2 barrier layer.

Crosslinked pyrrolidinium-based poly(ionic liquids) (Pyrr-PILs) were synthesized through a fast, simple, and solventless photopolymerization scheme, and tested as solid phase microextraction (SPME) sorbents. A series of Pyrr-PILs bearing three different alkyl side chain lengths with two, eight, and fourteen carbons was prepared, characterized, and homogeneously coated on a steel wire by using a very simple procedure. The resulting coatings showed a high thermal stability, with decomposition temperatures above 350 degrees C, excellent film stability, and lifetime of over 100 injections. The performance of these PIL-based SPME fibers was evaluated using a mixture of eleven organic compounds with different molar volumes and chemical functionalities (alcohols, ketones, and monoterpenes). The Pyrr-PIL fibers were obtained as dense film coatings, with 67 mu m thickness, with an overall sorption increase of 90% and 55% as compared to commercial fibers of Polyacrylate (85 mu m) (PA85) and Polydimethylsiloxane (7 mu m) (PDMS7) coatings, respectively. A urine sample doped with the sample mixture was used to study the matrix effect and establish relative recoveries, which ranged from 60.2% to 104.1%. David J. S. Patinha, and Liliana C. Tome are grateful to FCT (Fundacao para a Ciencia e a Tecnologia) for the PhD research grant SFRH/BD/97042/2013 and the Post-Doctoral research grant (SFRH/BPD/101793/2014), respectively. David J. S. Patinha also thanks the financial support from COST-Exil Project 1206. The NMR data was acquired at CERMAX (Centro de Ressonncia Magnetica Antnio Xavier) which is a member of the National NMR network. This work was partially supported by FCT through Research Unit GREEN-it " Bioresources for Sustainability" (UID/Multi/04551/2013) and the Associate Laboratory CICECO Aveiro Institute of materials (UID/CTM/50011/2013).

There is a growing interest in modern healthcare to develop systems able to fight antibiotic resistant bacteria. Antimicrobial cationic biodegradable polymers able to mimic antimicrobial peptides have shown to be effective against both Gram-positive and Gram-negative bacteria. In these systems, the hydrophilic-hydrophobic ratio and the cationic charge density play a pivotal role in defining the killing efficiency. Nevertheless, many of these antimicrobial polymers show relatively low selectivity as defined by the relative toxicity to mammalian cells or hemolysis relative to pathogens. In this study, a series of polycarbonates containing pendant quaternary ammoniums are used to understand the role of different counter-anions including chloride, citrate, malonate, benzoate, acetate, lactate and trifluoroacetate, and the antibiotic penicillin on antimicrobial efficacy and selectivity. Interestingly, it is found that in spite of the strong antimicrobial activity of trifluoroacetate and benzoate anions, they prove to be much less hemolytic than chloride anion. It is believed that the proper selection of the anion could enhance the potential of antimicrobial polymers to fight against clinically relevant pathogenic infections, while concurrently mitigating harmful side effects.

A simple method was developed for the preparation of polymeric materials with controlled surface wettability or tunable surface wetting. The method is applicable to a large number of polymers, thermoplastic or thermoset. With this method, it is possible to prepare polymer surfaces with static water contact angles ranging from 0° (superhydrophilic) to greater than 170° (superhydrophobic). The method developed is based on spin-coating of a hydrophilic/hydrophobic silica mixture dispersed in an organic solvent or solvent mixture onto the polymer surface. Depending on the hydrophilic/hydrophobic silica ratio in the coating mixture, it is possible to obtain polymer surfaces displaying gradually changing wettability from superhydrophilic to superhydrophobic. In this article, preparation and surface characteristics of polystyrene (PS) and cross-linked epoxy resin (ER) films are provided as general examples. Polymer surfaces obtained were characterized by scanning electron microscopy, white light interferometry, atomic force microscopy, X-ray photoelectron spectroscopy, and static water contact angle measurements. Effects of the type of polymeric substrate and composition of the silica mixture on the surface behavior of the composite systems were investigated.

A simple and general method has been developed for the preparation of polymeric materials with superhydrophobic surfaces. The process is applicable to a large number of polymers, thermoplastic or thermoset. In this manuscript preparation and characteristics of superhydrophobic surfaces prepared from a segmented polydimethylsiloxane–urea copolymer (TPSU), a polyether based polyurethaneurea (TPU), poly(methyl methacrylate) (PMMA), polystyrene (PS), polycarbonate (PC) and a crosslinked epoxy resin (EPOXY) are discussed. All samples were prepared onto glass surfaces by using a simple, multi-step spin-coating procedure. In the first step a thin film of the desired polymer was coated onto the glass slide. This was followed by spin-coating of two layers of hydrophobic fumed silica using a dispersion in tetrahydrofuran. Finally to obtain a durable surface, a very thin film of the parent polymer was spin-coated from a very dilute solution containing 2.5% by weight hydrophobic silica and 0.25% by weight matrix polymer in tetrahydrofuran. Surfaces were characterized by scanning electron microscopy (SEM), which clearly showed the formation of rough surfaces with homogeneously distributed silica particles in 1–10 μm range. Static water contact angle and contact angle hysteresis measurements proved the formation of superhydrophobic surfaces. Samples displayed static water contact angles larger than 170° and very low contact angle hysteresis of less than 3°.

Highly hydrophobic surfaces of silicone–urea copolymers were transformed into hydrophilic ones upon UV/ozone treatment. The extent of surface modification was strongly dependent on the sample preparation method and the exposure time. The physical and chemical changes at the copolymer surfaces were analyzed by spectroscopic (XPS, ATR-FTIR), microscopic (SEM) techniques and static water contact angle measurements. ATR-FTIR spectra clearly showed the dramatic change in the strongly hydrogen bonded urea hard segments and the degradation of dimethylsiloxane units in silicone–urea copolymers. XPS results revealed the formation of SiO x on the surface, which gradually increased with exposure time. After 3 h of UV/ozone exposure, Si(2p) binding energy shifted from 101.9 to 102.85 eV, which is a clear indication of an increase in the oxidation state of silicon. The deterioration of microroughness of the electrospun webs upon UV/ozone exposure, which was revealed by SEM, resulted in a dramatic decrease in the static water contact angle values from 129 to 62°. These results clearly show that UV/ozone process is a very simple and facile method to transform hydrophobic silicone–urea copolymer surfaces into fairly hydrophilic ones.

Novel segmented poly(urethaneurea) elastomers (TPUU) were prepared through the reaction of poly(tetramethylene oxide)glycols (PTMO-1000 and PTMO-2000) with excess aromatic diisocyanates (TDI and MDI), followed by in situ chain extension with water, through the formation of urea linkages. High molecular weight TPUU polymers with high urea hard segment (HS) contents of up to 44% by weight were obtained. FTIR analysis of the carbonyl region clearly showed the presence of strongly hydrogen bonded urethane and urea groups in the system. Dynamic mechanical analysis indicated the formation of microphase separated morphologies with well-defined PTMO glass transitions, followed by a composition dependent rubbery plateau extending well beyond 200 °C. Tapping mode AFM studies clearly indicated the formation of microphase morphology with hard urea domains dispersed or percolated through soft polyether matrix. Stress−strain tests demonstrated the formation of very strong elastomers with tensile strengths of up to 50 M...

There is a growing interest to develop green synthetic pathways towards industrially relevant polymers such as polyurethanes without the use of toxic and dangerous isocyanate monomers. The most promising route towards non-isocyanate polyurethanes (NIPUs) is the aminolysis of dicyclic carbonates derived from renewable resources. Although, cyclic carbonates of 5- and 6-members have been successfully proposed, aminolysis of these compounds requires the use of high temperatures to obtain high conversions and subsequently high molecular weight NIPUs. Indeed, these cyclic carbonates do not allow the achievement of high molecular weight NIPUs using low reactive diamines analogous to two of the most industrially relevant aliphatic diisocyanates. Herein, we report a (bis) N-substituted 8-membered cyclic carbonate that could be prepared from naturally abundant epoxides, diamines and dimethyl carbonate using sustainable chemical routes. This N-substituted 8 membered cyclic carbonate appeared to be much more reactive than the smaller 5- and 6-membered cyclic carbonates. Due to this increased reactivity, we obtained high molecular weight NIPUs using a variety of diamines, including industrially relevant hindered aliphatic diamines, such as 5-amino-1,3,3-trimethylcyclohexanemethylamine (IPDA) and 4,4’-methylenebis(cyclohexylamine). The synthesis of NIPUs was demonstrated at room temperature without the need for any additional catalyst. Altogether, this paper shows that (bis) N-substituted 8-membered cyclic carbonates are ideal starting materials for the synthesis of sustainable non-isocyanate polyurethanes (NIPUs). he authors would like to thank the European Commission for its financial support through the projects Renaissance-ITN 289347, OrgBIO-ITN 607896 and SUSPOL-EJD 642671. Haritz Sardon gratefully acknowledges financial support from MINECO through project SUSPOL and FDI 16507. Yi Yan Yang gratefully acknowledges financial support from Institute of Bioengineering and Nanotechnology (Biomedical Research Council, Agency for Science, Technology and Research, Singapore). We are also thankful for the technical and human support provided by IZO-SGI SGIker of UPV-EHU and European funding (ERDF and ESF).

Polymeric ionic liquids (PlLs) are blossoming as a nevv generation of materials aL the interface of many areas leading to a renaissance of the field of ionic polymers. Although PlLs are interesting membranes materials for CO2 separation, additional research is still required to realize their full potential. In this work, pyrroliclinium-based polymers containing different cyano-functionalized counter -anions were synthesized by straightforvvarcl anion exchange reactions and characterized. Their film forming ability blended with different amounts of free ionic liquid (IL) was evaluated and the CO2 and N-2 permeation properties through the prepared composites were determined. The results show that increasing the IL content in the composites not only increased CO2 permeability but also boosted the CO2/N-2 permselectivity, leading to improved separation performances. The best performance was achieved for the C(CN)(3)-based membrane containing 60 wt% of IL, which overcomes the Robeson 2008 upper bound, with CO2 permeability of 439.3 Bat rer and CO2/N-2 permselectivity of 64.4. Therefore, the pyrrolidinium-based PIL combined with the [C(CN)(3)](-) as counter-anion has potential for efficient post-combustion CO2 separation, suggesting the preparation of high performance membranes for industrial applications. (C) 2015 Elsevier B.V. All rights reserved.