Covalent immobilization of an antimicrobial peptide on poly(ethylene) film

An antimicrobial film was produced by covalently attaching synthetic peptide E14LKK to poly(ethylene) film. E14LKK is a 14 residue, magainin‐class peptide with broad‐spectrum antimicrobial activity. The poly(ethylene) surface was first oxidized with chromic/sulphuric acid, then PEGylated by using carbodiimide chemistry to attach ω‐amino‐α‐carboxyl‐poly(ethylene glycol) (PEG). The peptide was covalently coupled to the free terminus of the PEG, again using carbodiimide coupling. Surface contact angles for distilled water decreased from 101° initially to 61° following oxidation and 45° following PEGylation. Film surface chemistry showed the expected changes during the modifications: dye adsorption assays indicated changes in the number of acidic and basic groups and X‐ray photoemission spectroscopy showed increasing oxygen and nitrogen levels. Antimicrobial activity was demonstrated in broth cultures against E.coli: growth was reduced by atleast 3 log cycles compared to controls. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surface modification of cellulose nanocrystals by grafting with poly(lactic acid)

The use of biopolymers obtained from renewable resources is currently growing and they have found unique applications as matrices and/or nanofillers in ‘green’ nanocomposites. Grafting of polymer chains to the surface of cellulose nanofillers was also studied to promote the dispersion of cellulose nanocrystals in hydrophobic polymer matrices. The aim of this study was to modify the surface of cellulose nanocrystals by grafting from L‐lactide by ring‐opening polymerization in order to improve the compatibility of nanocrystals and hydrophobic polymer matrices. The effectiveness of the grafting was evidenced by the long‐term stability of a suspension of poly(lactic acid)‐grafted cellulose nanocrystals in chloroform, by the presence of the carbonyl peak in modified samples determined by Fourier transform infrared spectroscopy and by the modification in C1s contributions observed by X‐ray photoelectron spectroscopy. No modification in nanocrystal shape was observed in birefringence studies and transmission electron microscopy. © 2013 Society of Chemical Industry     

Hydrolysis of poly(l-lactide)/ZnO nanocomposites with antimicrobial activity

This work investigates the effect of the incorporation of zinc oxide (ZnO) nanoparticles within a poly(l -lactic acid) (PLLA) matrix as an approach to speed up the hydrolysis of PLLA film surfaces. Hydrolysis was done by immersing nanocomposite films having 1 wt % of ZnO in 0.25 M sodium hydroxide at 58 °C. This concentration has been selected as it provides the maximum changes of physicochemical properties of hosting PLLA matrix. The evolution of the thermal properties, ultraviolet–visible transparency, wettability, and morphology were monitored at different time points. The amount of carboxylic groups onto PLLA/ZnO surfaces was quantified according to Toludine Blue-O assay. Hydrolysis was mainly limited to film surfaces, which were grafted by carboxylic groups as a result of the random scission of PLLA ester linkages. The presence of such functional groups decreases the inherent surface hydrophobicity of PLLA at short hydrolysis times. On the contrary, long hydrolyses increase the hydrophobicity as a result of surface nanostructuring induced by the degradation of PLLA to water-soluble oligomers. Overall, ZnO nanoparticles enable shorter surface modification times and provide a quick approach for the modification on the polarity of polylactide surfaces. The potential of hydrolyzed films as antimicrobial materials was explored using Gram-negative Escherichia coli as a model. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47786.     

Thermal energy storage by poly(styrene-co-p-stearoylstyrene) copolymers produced by the modification of polystyrene

A series of poly(styrene-co-p-stearoyl styrene) copolymers as novel polymeric solid–solid phase-change materials (SSPCMs) were synthesized by the modification of polystyrene with stearoyl chloride. The chemical structure and crystalline morphology of the synthesized copolymers were determined with Fourier transform infrared spectroscopy and polarized optical microscopy, respectively. The thermal energy storage properties and thermal stability of the SSPCMs were investigated with differential scanning calorimetry and thermogravimetric analysis, respectively. In addition, the thermal conductivity of the SSPCMs was measured with a thermal property analyzer. Moreover, thermal cycling tests showed that the copolymers had good thermal reliability and chemical stability after being subjected to 5000 heating/cooling cycles. The synthesized poly(styrene-co-stearoyl styrene) copolymers as novel SSPCMs have considerable potential for thermal energy storage and temperature-control applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

远程等离子体处理对聚四氟乙烯表面的功能化改性

采用远程氩等离子体对聚四氟乙烯(PTFE)膜进行了表面改性研究,通过接触角测定仪、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等手段,分析研究了改性后材料表面结构、性能的变化。结果表明:PTFE表面经远程氩等离子体处理后,表面微观形态和表面化学成分均发生了变化,且处理效果优于常规氩等离子体。远程氩等离子体可以在一定程度上抑制电子、离子的刻蚀作用,强化自由基反应,使材料表面获得更好的改性效果。经远程氩等离子体短时间(100s)处理后,PTFE表面的F/C比例从1.97降至1.44,O/C比例从0.015增至0.086;表面的水接触角从108°减小到53°;表面自由能从22.4×10-5N·cm-1增加至52.3×10-5N·cm-1。     

Surface modification and degradation of poly(lactic acid) films by Ar-plasma

Surface modification of poly(lactic acid) (PLA) film surface by Ar-plasma was investigated by contact angle measurements and XPS in order to answer the following two questions. (1) Could the Ar-plasma modify the PLA film surfaces? (2) What chemical reactions occurred on the film surfaces during the Ar-plasma treatment? The Ar-plasma treatment did not lead to hydrophilic modification of the PLA film surface, but to degradation reactions of the PLA film. Poor modification may be due to instability of the carbon radicals formed from C—O bond scission in the PLA chains by the Ar-plasma.     

Surface segregation and miscibility in blends of poly(ethyl acrylate) with poly(vinylidene fluoride-co-hexafluoroacetone)

In blends of poly(ethyl acrylate) (PEA) and poly(vinylidene fluoride-co-hexafluoroacetone) [P(VDF-HFA)], surface segregation of the P(VDF-HFA) component was confirmed by X-ray photoelectron spectroscopy. The PEA/P(VDF-HFA) blends exhibited lower critical solution temperature phase behaviour, with a critical temperature of 150°C. Since the surface tension value of P(VDF-HFA) is lower than that of PEA, this may influence surface segregation behaviour in PEA/P(VDF-HFA) blends. Surface segregation results of the PEA/P(VDF-HFA) blends are compared with those from a previous study on immiscible acrylate copolymer/fluoro copolymer blends.     

Surface modification of poly(tetrafluoroethylene) and poly(ethylene terephthalate) films via environmental crazing

This work addresses the phenomenon of the development of a patterned surface relief on polymer films via different modes of environmental crazing. Commercial films of semicrystalline poly(tetrafluoroethylene) (PTFE) and amorphous glassy poly(ethylene terephthalate) (PET) were subjected to tensile drawing in the presence of physically active liquid environments (carbon tetrachloride or aliphatic alcohols). The structure parameters and wettability of the modified films were studied by AFM, SEM, profilometer measurements and contact angle measurements. Environmental intercrystallite crazing of PTFE is accompanied by the development of an unstable structure with a high free surface, which experiences marked strain recovery upon unloading. As a result of the relief formation, PTFE hydrophobicity is enhanced (the water contact angle increases by 25°). Classical environmental crazing of PET films is accompanied by the formation of an anisotropic surface relief which is an assembly of crazes oriented perpendicular to the direction of tensile drawing, thus leading to the phenomenon of anisotropic wetting. The proposed approach for structural surface modification makes it possible to use the advantages of surface instability and spontaneous self‐organization of the polymer towards the development of a unique surface microrelief. © 2020 Society of Chemical Industry     

Surface segregation of components in poly(vinyl chloride)–polydimethylsiloxane and polystyrene–poly(propylene oxide) solvent-cast blends

X-ray photoelectron spectroscopy and scanning electron microscopy are used to study the surface composition and morphology of poly(vinyl chloride)–polydimethylsiloxane (PVC–PDMS) and polystyrene–poly(propylene oxide) (PS–PPO) solvent-cast blends as a function of the blend composition and constituent molecular weights. The PVC–PDMS blends show a pronounced surface enrichment of PDMS, which is higher the lower the molecular weight of PDMS. The surface behavior ofthe PPO–PS blends is strongly dependent on the solvent used. Despite the much lower surface tension of PPO compared to that of PS, no surface segregation of PPO isobserved in the PPO–PS blends cast from tetrahydrofuran, while the blends cast from chloroform exhibit a high surface enrichment of PPO. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 517–522, 1998     

Effect of annealing on poly(urethane‐siloxane) copolymers

The N‐substituted polyaniline (PANi) was synthesized by incorporation of bromine‐terminated polystyrene (PS‐Br) onto the emeraldine form of polyaniline. End brominated polystyrene was synthesized by atom transfer radical polymerization (ATRP) technique and then deprotonated polyaniline was reacted with PS‐Br to prepare PS‐grafted PANi (PS‐g‐PANi) copolymer through N‐grafting reaction. The degree of N‐grafting can be controlled by adjusting the molar feed ratio of PS‐Br to the number of repeat units of PANi. The microstructure and compositions of the PS‐g‐PANi copolymers with different degrees of N‐substitution were characterized by FT‐IR, elemental analysis, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The cyclicvoltammetry shows that the electroactivity of N‐substituted PANi is strongly dependent on the degree of N‐grafting. The solubility of PS‐g‐PANi copolymers in common organic solvents such as tetrahydrofuran and chloroform was improved by increasing the degree of N‐grafting, and also the samples are partially soluble in xylene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Surface modification of poly(vinyl chloride) for antithrombogenicity study

A process was established to conduct heparinization on the surface of poly(vinyl chloride) for antithrombogenicity utilization. A bifunctional monomer, glycidyl methacrylate (GMA), was grafted onto the surface of PVC by gas‐phase photografting polymerization without degassing first; then heparin was immobilized onto the poly(glycidyl methacrylate) segments. The branch structure of GMA and heparin were characterized by Fourier transfer infrared (FTIR) spectroscopy and electron spectroscopy (ESCA). It was confirmed that the bifunctional monomer GMA and heparin were grafted successfully onto the surface of PVC. The antithrombogenicity of the samples was tested both in vitro and in vivo, respectively. Results indicated that the blood compatibility of those products was improved greatly. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1013–1018, 2002     

家蝇抗菌肽祛痘功效性评价及其产品开发

采用肉汤稀释法测得家蝇抗菌肽对痤疮丙酸杆菌(Propionibacterium acnes)的最低抑菌浓度(MIC)为0.078 mg/mL.根据GB 15979-2002《一次性使用卫生用品卫生标准》中附录C4“溶出性抗(抑)菌产品抑菌性能试验方法”,测得家蝇抗菌肽在添加质量分数为1％,2％,3％和5％时的抑菌率分别为34.21％,42.42％,99.99％和99.99％.根据QB/T1857-2004中润肤膏霜的卫生指标及感官、理化指标的试验方法及检验标准对该祛痘产品进行检测,结果表明各项指标均符合标准中的要求,且进一步的加速稳定性试验表明,产品的稳定性较好,未见分层、变色、变质和变味等现象的发生.     

Surface modification of poly(tetrafluoroethylene) with pulsed hydrogen plasma

Surface modification of polymers by pulsed plasma has been investigated to minimize degradation reactions occurring at the same time as the surface modification reactions. The hydrogen radical, ion, and electron concentrations in the hydrogen plasma were simulated as a function of the elapsed time after turning off the discharge. The contact angle measurement showed that hydrogen plasma treatment, regardless of pulsed or continuous plasma, led to degradation reactions as well as defluorination and oxidation on PTFE surfaces. The degradation reactions of PTFE chains initiated by the pulsed hydrogen plasma were not as vigorous as those by the continuous hydrogen plasma. A combination of the on‐time/off‐time of 30/270μs in the pulsed hydrogen plasma was efficacious in modifying PTFE surfaces. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 340–348, 2002     

Surface modification of poly(tetrafluoroethylene) film by chemical etching,plasma, and ion beam treatments

Chemical etching, plasma, and ion beam treatments were used to modify the surface of Polytetrafluoroethylene (PTFE). Each surface treatment method developed different surface characteristics. In addition to morphological observation, contact angle, atomic chemical composition, and adhesion strength were measured after treatment with various methods. The different adhesion strengths were explained based on the morphology and atomic chemical composition of the treated PTFE surfaces. The chemical etching showed substantial defluorination, and the adhesion strength was fairly high. The argon plasma treatment introduced very large amounts of oxygen into the surface, and the surface was very smooth with a crater‐like structure. Ion beam treatment induced a form of spires whose dimensions were of several micrometers, depending on the ion dose, whereas the oxygen plasma‐treated samples showed short spires with spherical particles on the top. The spire‐like surface morphology and increased surface area during bonding by ion beam treatment appear to be the reason for a higher adhesion strength than that of the oxygen plasma‐treated PTFE. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1913–1920, 2000     

Surface modification of poly(vinyl chloride) using high intensity ultrasound

The use of high intensity ultrasound to promote a number of reactions at the surface of solid poly(vinyl chloride) is reported. Substitution reactions involving a range of compounds, including dyes, can rapidly be carried out from aqueous solution under labile conditions. Sonochemically enhanced treatment with strong aqueous base produces dehydrochlorination even at room temperature to produce a thin layer of conjugated material at the surface which can then be grafted with a number of compounds. Some speculation as to the mechanistic features of the process as well as its potential utility is made. © 1999 Society of Chemical Industry     

Surface modification of poly(tetrafluoroethylene) film by plasma graft polymerization of sodium vinylsulfonate

Poly(tetrafluoroethylene) (PTFE) surface was modified by the graft polymerization of sodium vinylsulfonate, and the chemical composition of the graft-polymerized PTFE surface was analyzed by X-ray photoelectron spectroscopy. Peroxides were formed on the PTFE surface by a combination procedure of argon plasma irradiation and air exposure, and the graft polymerization of sodium vinylsulfonate was initiated by the peroxide groups at 65–80°C. The peroxide concentration is 3 × 10⁺¹³ to 5 × 10⁺¹³ numbers/cm². The average degree of polymerization of the graft polymers was 3.4 × 10³. The graft polymer is distributed over the PTFE surface, but part of the PTFE surface remains uncovered. The coverage with the graft polymer is 43%. The PTFE surface graft polymerized with sodium vinylsulfonate was somewhat hydrophilic, but the hydrophilicity was lower than that of the PTFE surface modified by plasma treatment. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 77–84, 1997     

Surface modification of silicone rubber by ion beam assisted deposition (IBAD) for improved biocompatibility

We studied the preparation of antimicrobial silicone rubbers of improved interfacial strength, which could be formed with the ion beam assisted deposition (IBAD) technique for coating metallic or inorganic materials (silver (Ag), Copper (Cu), and Hydroxyapatite(HAp)/TiO₂) on the silicone surface. Those coating materials provide high product safety as well as outstanding antimicrobial activity. The deposition methodology is composed of pre‐etching with oxygen gas, vaporizing the coating materials, and post‐treatment with Ar ion. With the evaporation of the coating materials, the Ar beam was focused on the substrate to assist deposition. It was found out that the ion assisting depositions in the IBAD process give a prominent enhancement in adhesion between silicone rubbers and coatings of Ag and Cu. The HAp/TiO₂ coating layer was easily dissolved in aqueous saline solution. All deposited layers display high antimicrobial activities against Staphlococcus aureus (ATCC 6538) and Escherichia coil (ATCC 25,922), showing 99.9% reduction of bacteria, respectively. In a cytotoxicity test, the Ag and HAp/TiO₂ coated silicone shows a decrease of cytotoxicity, while the Cu coating leads to a slight increase of cytotoxicity. The result on the surface modifications of silicone rubber will be employed in further study for applications of medical or rehabilitation devices. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1095–1101, 2005     

Surface modification of poly(ethylene terephthalate) film by coating with poly(ethylene glycol)‐grafted polystyrene

The poly(ethylene glycol) (PEG)‐grafted styrene (St) copolymer, which was formed as a nanosphere, was used as an agent to modify the surface of poly(ethylene terephthalate) (PET) film. The graft copolymer was dissolved into chloroform and coated onto the PET film by dip–coating method. The coated amount depends on the content ratios of PEG and St, the solution concentration, and the coating cycles. The graft copolymers having a low molecular weight of PEG‐ or St‐rich content was fairly stable on washing in sodium dodecyl sulfate (SDS) aqueous solution. It was confirmed that the PET surface easily altered its surface property by the coating of the graft copolymers. The contact angles of the films coated with the graft copolymers were very high (ca. 105–120°). The coated film has good antistatic electric property, which agreed with PEG content. The best condition of coating is a one‐cycle coating of 1% (w/v) graft copolymer solution. The coated surface had water‐repellency and antistatic electric property at the same time. The graft copolymer consisted of a PEG macromonomer; St was successfully coated onto PET surfaces, and the desirable properties of both of PEG macromonomer and PSt were exhibited as a novel function of the coated PE film. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1524–1530, 1999     

Polymer blends of poly(trimethylene terephthalate) and polystyrene compatibilized by styrene‐glycidyl methacrylate copolymers

The compatibilizing effects of styrene‐glycidyl methacrylate (SG) copolymers with various glycidyl methyacrylate (GMA) contents on immiscible blends of poly(trimethylene terephthalate) (PTT) and polystyrene (PS) were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and ¹³C‐solid‐state nuclear magnetic resonance (NMR) spectroscopy. The epoxy functional groups in the SG copolymer were able to react with the PTT end groups (? COOH or ? OH) to form SG‐g‐PTT copolymers during melt processing. These in situ–formed graft copolymers tended to reside along the interface to reduce the interfacial tension and to increase the interfacial adhesion. The compatibilized PTT/PS blend possessed a smaller phase domain, higher viscosity, and better tensile properties than did the corresponding uncompatibilized blend. For all compositions, about 5% GMA in SG copolymer was found to be the optimum content to produce the best compatibilization of the blend. This study demonstrated that SG copolymers can be used efficiently in compatibilizing polymer blends of PTT and PS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2247–2252, 2003