Simultaneous graft copolymerization of 2‐hydroxyethyl methacrylate and acrylic acid onto polydimethylsiloxane surfaces using a two‐step plasma treatment

Acrylic acid (AAc) and 2‐hydroxyethyl methacrylate (HEMA) mixtures were simultaneously grafted onto the surfaces of polydimethylsiloxane (PDMS) films using a two‐step oxygen plasma treatment (TSPT). The first step of this method includes: oxygen plasma pretreatment of the PDMS films, immersion in HEMA/AAc mixtures, removal from the mixtures, and drying. The second step was carried out by plasma copolymerization of preadsorbed reactive monomers on the surfaces of dried pretreated films. The effects of pretreatment and polymerization time length, monomer concentration, and ratio on peroxide formation and graft amount were studied. The films were characterized by attenuated total reflection Furrier transformer infrared (ATR‐FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential, surface tension, and water contact angle measurements. The ATR‐FTIR spectrum of the modified film after alkaline treatment showed the two new characteristic bands of PHEMA and PAAc. Both increase the polar part of surface tension (γ_p) after grafting and the evaluation of surface charge at pH 1.8, 7, and 12 confirmed the presence of polar groups on the surface of grafted films with a mixture of HEMA/AAc. Morphological studies using both AFM and SEM evaluation illustrated various amounts of grafted copolymer on the surface of PDMS films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Structural characterization of alpha methyl styrene‐butyl acrylate‐grafted polyetheretherketone films

Radiation‐induced graft copolymerization of alpha methyl styrene (AMS)‐butyl acrylate (BA) mixture onto poly(etheretherketone) (PEEK) was carried out to develop films of varying copolymer compositions. The characterization of films was carried out with fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), X‐ray diffraction analysis (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The presence of AMS and BA units within the film matrix was confirmed by FTIR. The intensity of the characteristic peaks for AMS and BA increased with the increasing grafted component in the films. The crystallinity of the films as observed from DSC and XRD decreased with the increasing graft levels. On the other hand, the melting temperature of the base polymer was almost unaffected by irradiation and the grafting process. The glass transition temperature (T_g) of the grafted film increased as compared to the virgin PEEK. Ungrafted film showed a stable thermogram up to ～500°C. However, the grafting introduced a new decomposition range in the copolymer, due to the presence of the AMS/BA. AFM images showed the formation of domains on the grafted PEEK film surface. The SEM also showed domain formation of the grafted component within the PEEK matrix. However, the fracture analysis did not show any prominent phase separation. Mechanical characterization of films in terms of tensile strength, elongation, and modulus was also carried out. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of thermal oxidation on surface and thermo-mechanical properties of polyethylene

Blown low density polyethylene (LDPE) films added with oxo-biodegradable additive containing pro-oxidant were subjected to thermo-oxidation in an oven at 70 °C for varying time periods. The changes in mechanical and surface properties were studied using tensile strength, elongation at break, wettability, surface morphology using SEM, surface topology by AFM, functional groups by FTIR spectroscopy, absorbance spectra by UV-Vis spectroscopy. The thermally aged films with pro-oxidant additive added polyethylene (PE) exhibited a higher level of oxidation as revealed by increase in their carbonyl index than the pristine PE. In addition to it, the DSC melting behavior showed a slight increase in crystallinity (%C) and melting temperature (Tm) of the polymer containing oxo-biodegradable additive. The SEM micrograph reveals the increase in the size of cracks and grooves, according to the increase in the concentration of pro-oxidant additive. The surface roughness also supports the same through AFM image. The increase in the wettability and surface free energy of the thermally aged samples were attributed to the formation of hydrophilic groups on the polymer surface by thermo-oxidation. The pro-oxidant additive offers a new insight into the thermo-oxidation strategy for PE and can be widely used in packaging industry.     

High refractive index transparent coatings obtained via UV/thermal dual-cure process

Nanostructured organic-inorganic hybrid epoxy coatings containing zirconia domains were obtained via a cationic UV/thermal dual-cure process. Uniform distribution of the in situ generated zirconia within the polymeric network on a nanometric scale (5-25 nm) was demonstrated by AFM and TEM analyses. The UV-cured films showed increase of the refractive index by increasing the zirconium tetrapropoxide content in the photocurable formulation. Coatings with a drastic cut-off in the UV spectra still maintaining transparency in the visible light were achieved. These coatings could find advanced applications as antireflection coatings, or in the optical industry.     

Sol-gel synthesis of polyaniline/zirconia composite conducting materials

Polyaniline (Pani) conducting polymer was successfully synthesized by an emulsion polymerization of aniline monomer in the presence of dodecyl benzene sulfonic acid (DBSA). Consequently novel Pani.DBSA/zirconia composites (PDZr) were successfully synthesized by sol-gel technique. Structural and morphological characterization of PDZr composites were carried out using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Upon incorporating zirconia the resulting composite material showed greater crystallinity. The FT-IR spectrum showed the characteristic peaks of Pani.DBSA shifted to higher wavenumbers. This suggests some interactions between zirconia network and Pani.DBSA polymer chains. TEM micrographs indicate morphological changes upon the formation of PDZr composites. The nanoparticles of Pani.DBSA formed rod-like structures in the resulting composite materials. A higher electrical conductivity was obtained when the PDZr composite was incorporated with 30 % weight of Zr(IV)-n-propoxide. Differential scanning calorimetry (DSC) measurements revealed two distinct glass transition temperature (T_g) for PDZr composite at low percentage of zirconia. Thermogravimetric analysis (TGA) results indicate that the maximum degradation temperature of the PDZr composites increased significantly to 484 °C.     

Morphological and Mechanical Properties of Poly (Vinyl Alcohol) Doped with Inorganic Fillers

A number of polymer composite films using polyvinyl alcohol (PVA) as the preorganized polymer matrix were synthesized embedding different metal salts of transition elements like copper, cobalt, nickel, iron, cadmium, and zinc by a biomimetic route. The metal salts present in composites were reduced in situ to metallic form. The composites were characterized by FTIR, SEM, and EDAX. The SEM analysis confirmed the presence of nano-sized metal particles uniformly distributed in the polymer matrix. Mechanical properties were measured for various composite and PVA films. Significant improvement in some of the mechanical properties of polymer composites was realized in comparison with PVA.     

Electrochemical preparation of pyronin Y thin films on gold substrates

Cyclic voltammetry, chronoamperometry, UV‐vis absorption spectroscopy, fluorescence spectroscopy, FTIR spectroscopy, and AFM techniques have been employed to investigate pyronin Y thin films formed on Au(111) substrates by electrochemical oxidation of pyronin Y monomer. The medium used in the electropolymerization was an anhydrous acetonitrile solution containing 0.1M TBAClO₄ as supporting electrolyte. Anodic electropolymerization potential (1450 mV) of pyronin Y has been obtained from cyclic voltammetry data. Solid‐state electropolymerization of pyronin Y was performed by the potential‐controlled electrolysis technique. Chronoamperometry studies indicate that the adsorption of pyronin Y takes place in an instantaneous three‐dimensional nucleation and growth mechanism which is accompanied by random adsorption. UV‐vis absorption and fluorescence spectra of the electrolysis solution as a function of electrodeposition time show the adsorption of insoluble pyronin Y films on Au electrode surface. FTIR‐specular reflectance of a polymer coated Au electrode reveals that there is a possible C? C coupling in the formation of polymeric pyronin Y structure. A well ordered polymeric chain structure of pyronin Y on Au(111) has been observed from AFM data. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

芳纶纳米纤维增强聚乙烯醇复合膜的制备与性能

以芳纶纤维Kevlar@49为原料,在温和条件下制备了芳纶纳米纤维分散体(ANFS),并利用分散体制备了芳纶纳米纤维/聚乙烯醇(ANFs/PVA)复合膜。通过傅里叶红外光谱(FTIR)仪、差示扫描量热(DSC)仪、原子力显微镜(AFM)、扫描电子显微镜(SEM)、电子万能试验机及透光度/雾度测定仪等考察了复合膜的微观结构、热学、光学及力学性能。FTIR证明,复合膜中ANFs与PVA具有一定的分子间氢键作用,促进了ANFs在PVA基体中的分散。由AFM和SEM可以清晰观察到直径为20~30 nm的芳纶纳米纤维分散体,并且通过SEM观察到复合膜表面较为平整。当芳纶纳米纤维质量分数为6.0%时,复合膜的抗拉强度为17.86 MPa,断裂伸长率为442%;透光度为82.63%,雾度为27.56%;玻璃化温度,熔融温度和结晶温度分别为75.20、208.82和174.51℃,表明其透光性良好,力学和热学性能达到最佳。     

Simple route for the preparation of graphene/poly(styrene‐b‐butadiene‐b‐styrene) nanocomposite films with enhanced electrical conductivity and hydrophobicity

This paper reports a simple route for the preparation of graphene/poly(styrene‐b‐butadiene‐b‐styrene) (SBS) nanocomposite films employing a vacuum filtration method. Graphene is exfoliated well by an electrochemical procedure and homogeneously dispersed in the polymer matrix. The prepared nanocomposite films were characterized by XRD, Fourier transform IR (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), Raman spectroscopy, AFM and SEM. Morphological studies showed that graphene formed a smooth coating over the surface of SBS. The increase in graphene concentration induces the wrinkling of graphene sheets at the composite surface which causes a further increase in surface roughness. The FTIR, Raman and XPS spectra of graphene/SBS nanocomposite films indicate the strong interactions between graphene and the polymer matrix. According to the XRD patterns, introducing SBS into graphene did not modify the graphene structure additionally, i.e. the crystal lattice parameters do not depend on SBS content in graphene/SBS nanocomposite films. The graphene/SBS nanocomposite films also exhibited better hydrophobicity due to the increased surface roughness and lower sheet resistivity (reduced 10 times) compared to exfoliated graphene. © 2018 Society of Chemical Industry     

Electrochemical synthesis and characterization of poly-2-aminothiazole

2-Aminothiazole (2AT) was electrochemically polymerized on a Pt electrode using cyclic voltammetry (CV) technique from 0.01 M monomer containing 0.3 M ammonium oxalate solution. The high quality poly-2-aminothiazole (pAT) films with a light-brownish color were obtained on the Pt surface. The electrochemical behavior of the pAT-coated Pt electrode (Pt/pAT) was investigated in monomer-free 0.3 M ammonium oxalate solution by CV technique. The chemical structure characterization was investigated by UV–vis spectroscopy (UV–vis) and Fourier transform infrared spectroscopy (FTIR) techniques. The surface morphology of the polymer film was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface morphology studies showed that, a homogeneous and compact film was formed on the Pt surface. Further, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) techniques were used to investigate the thermal properties of the polymer film. It was found that the thermal stability of the pAT film is relatively high. The solubility of the pAT was tested in common organic solvents as well as in acidic and basic solutions.     

Degradation of polyester film in alkali solution

In recent years there has been a remarkable growth in coatings technology, yet polymer‐coated metals still corrode when they are exposed to severe environments. If the effectiveness of polymer coatings is to be increased, it is essential to understand the microstructure of polymer coating film and the changes that occur to the film upon environmental exposure, and relate the changes to the protective performance of coatings. The degradation of a polyester immersed in alkali solution has been investigated using a number of analytical techniques including atomic force microscopy (AFM), liquid chromatography/mass spectrometry (LC/MS), and Fourier transform infrared spectroscopy (FTIR). AFM was used to characterize the heterogeneous phase in the unexposed films and films exposed to alkali solution. Film roughness was found to increase with aging of the film in alkali medium. Total organic carbon analysis of the leached aqueous medium showed the presence of organic compounds, suggesting a chemical degradation of the film in alkali medium. FTIR analysis of the leached medium showed evidence for the formation of carboxylate species upon degradation of polyester film in alkali solution, while LC/MS analysis of the leached medium confirmed the presence of isophthalic acid and sodium isophthalate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2454–2463, 2000     

Preparation and characterization of PS‐PMMA/ZnO nanocomposite films with novel properties of high transparency and UV‐shielding capacity

High transparent and UV‐shielding poly (styrene)‐co‐poly(methyl methacrylate) (PS‐PMMA)/zinc oxide (ZnO) optical nanocomposite films were prepared by solution mixing using methyl ethyl ketone (MEK) as a cosolvent. The films were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectra, high‐resolution transmission electron microscopy (HR‐TEM), and atomic force microscope (AFM). Cross‐section HR‐TEM and AFM images showed that the ZnO nanoparticles were uniformly dispersed in the polymer matrix at the nanoscale level. The XRD and FTIR studies indicate that there is no chemical bond or interaction between PS‐PMMA and ZnO nanoparticles in the nanocomposite films. The UV–vis spectra in the wavelength range of 200–800 nm showed that nanocomposite films with ZnO particle contents from 1 to 20 wt % had strong absorption in UV spectrum region and the same transparency as pure PMMA‐PS film in the visible region. The optical properties of polymer are greatly improved by the incorporation of ZnO nanoparticles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of transparent ultrahydrophobic silica film by sol�Cgel process

Transparent ultrahydrophobic films were synthesized by sol–gel process with organic silicones modified into silica sol and cured under UV irradiation. The effects of hydrolysis temperature, hydrolysis time, molar ratio of organic silicone to silica sol, and surface morphology on the hydrophobicity of the films were discussed in detail using FTIR spectroscopy, scanning electron microscopy (SEM), AFM, optical transmission, and contact angle measurement, respectively. The AFM and SEM images indicated that the surface roughness enhanced the hydrophobicity of the films. The results revealed that methyl-trimethoxysilane (MTMS)-modified silica film prepared at 50°C for 2 h with an MTMS/silica sol molar ratio of 1:10 had a very high contact angle (130°). However, the higher hydrolysis temperature and longer reaction time might have accelerated the self-condensation of silanol and decreased the contact angle of the films.     

Preparation,mechanical properties and surface morphologies of waterborne fluorinated polyurethane-acrylate

A series of waterborne fluorinated polyurethane-acrylate (WFPUA) materials were prepared from polyester polyol (NJ-330), isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and different content of hexafluorobutyl acrylate (FA). The chemical structure was characterized with FT-IR, ¹H and ¹³C NMR; and the result confirmed that the FA monomer had been introduced into the chain of the WPUA polymer. The physical properties of WFPUA dispersions, mechanical properties and thermal properties of WFPUA films were measured. When the content of FA monomer was 3.0 wt.%, the film exhibited the highest tensile strength, hardness and excellent chemical resistance. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used for characterization of cross and surface sections of the WFPUA films to verify the results. The obtained WFPUA materials have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.     

Novel high-strength montmorillonite/polyvinyl alcohol composite film enhanced by chitin nanowhiskers

Nanomaterials can be used as reinforcement phase to improve the performance of polymers. A simple method to prepare a composite film with super high tensile strength was used in this study. The properties of montmorillonite (MMT)/polyvinyl alcohol (PVA) films reinforced by chitin nanowhisker (CNW) have been evaluated. The structures and properties of films were analyzed by atomic force microscope (AFM), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile testing. The results of FTIR and XRD showed that no chemical interaction occurred among MMT, PVA, and CNW. The SEM and AFM images suggested that the obtained composite films with the three substances had a relatively uniform layered structure and relatively smooth. The temperature at the onset of decomposition of the composite films was increased from 262.0 to 282.3°C by the addition of CNW. The tensile strength of the MMT/PVA/CNW film was reached 263.5 MPa, which was increased approximately 382% compared with the MMT/PVA film. According to these results, the composite film could be potentially used in packaging materials.     

AFM/FTIR: A New Technique for Materials Characterization

A new type of infrared spectroscopy for obtaining the molecular composition of the surfaces of materials at ultra-high spatial resolution has been developed by combining atomic force microscopy (AFM) with Fourier-transform infrared spectroscopy (FTIR). This new analytical technique involves the use of an AFM to detect the response of a material to the absorption of modulated infrared radiation from an FTIR spectrometer and is referred to as AFM/FTIR spectroscopy. When the technique of AFM/FTIR spectroscopy is completely developed, we plan to use it to probe the molecular structure of interphases in polymer composites and adhesive bonds. Two approaches have been used to measure the response of polymer systems to infrared absorption. The first involves the use of a contact mode AFM probe to measure the thermal expansion of the polymer; the second involves using a scanning thermal microscopy (SThM) probe to measure the polymer's temperature increase. In either case, the output of the probe resembles an interferogram to which a Fourier-transform can be applied to obtain the infrared absorption spectrum. The first approach was used to obtain excellent quality AFM/FTIR spectra from various neat polymer films, including polystyrene, polycarbonate, and a model adhesive system consisting of an epoxy resin cross-linked with dicyandiamide. Excellent spectra were also obtained from polystyrene beads having a diameter of about 2 µm. The second approach, using an SThM probe to determine the temperature increase that accompanies infrared absorption, was also used to obtain interferograms of polymer samples such as polystyrene. However, the interferograms were noisy and the AFM/FTIR spectra obtained from them had a low signal-to-noise ratio. The present results, thus, show that AFM/FTIR spectroscopy is feasible but the spatial resolution of the technique remains to be shown.     

醇-水盐溶液加热法制备纳米氧化锆工艺研究

以氧氯化锆为原料,通过醇水环境下的水解反应制得溶胶状锆盐,经过超声波分散和氨水沉淀等过程制得氧化锆前躯体,再经干燥和焙烧制备出纳米氧化锆。采用红外光谱（IR）、X射线衍射（XRD）及扫描电镜（SEM）等对合成过程和最终产品的性能进行了测试和表征。结果表明,在醇水体积比为5∶1、锆盐浓度为0.1 mol/L、聚乙二醇用量为10%（物质的量分数）、焙烧温度为650 ℃条件下,可制备出纳米氧化锆粉体,其分散性好且颗粒细小均匀。     

Effect of Substrate Temperatures on Structural and Morphological Properties of Nano-Crystalline Silver Thin Films Grown on Silicon Substrates

The silver (Ag) thin films were deposited on silicon substrates by DC magnetron sputtering method under different substrate temperatures of 100–500?°C. Then the as-deposited films were subjected to annealing treatment. The XRD results revealed that the Ag thin films have a good nanocrystalline structure and a considerable increase in the crystallinity of Ag (111) peak was observed at substrate temperature of 200?°C. The average crystalline size of Ag films varied between 18 and 44 nm which confirms the presence of nanocrystal’s in the films. The AFM and SEM images demonstrated that the grain size and surface roughness of the films are sensitive to substrate temperature during deposition of the films and annealing treatment. The SEM results is in good agreement with the results of XRD and AFM analysis.     

The surface modification of medical polyurethane to improve the hydrophilicity and lubricity: The effect of pretreatment

The medical polyurethane (PU) film was grafted with poly(acrylic acid) (PAA) to improve the hydrophilic and lubricious properties. The influences of pretreatment by ozone or potassium peroxydisulfate on themorphologies of PU films and grafting results were systematically investigated. The grafted PU films were characterized using attenuated total reflection Fourier transformed infrared spectroscopy (ATR‐FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and gel permeation chromatography (GPC). The hydrophilic and lubricious properties were evaluated by water contact angle and friction coefficient, respectively. The results showed that PAA could be grafted firmly on PU activated by both ozone and potassium peroxydisulfate, and the PAA‐grafted PU showed good hydrophilic and lubricious performance. More importantly, the PAA‐grafted PU films with the pretreatment of ozone were better in surface roughness, hydrophilicty and lubricity, compared to those with the pretreatment of potassium peroxydisulfate. Hence, surface ozonation could be a better choice for the pretreatment of medical polymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Ethylene/ ammonia plasma polymer deposition for controlled adhesion of graphite fibers to PEEK

Plasma polymerization of ethylene and ammonia gas mixtures is used to obtain uniform polymer coatings on the surface of AS4 graphite fibers. The polymer deposition rates were determined for processing parameters such as composition of the monomer mix, monomer flow rate, chamber pressure, and power input of the radio frequency field. Plasma formed polymers were characterized using Fourier Transform Infrared (FTIR) and X-ray Photoelectron Spectroscopy (XPS). XPS spectra were collected at 75° and 30° takeoff angles to obtain elemental composition and functional group populations at different sampling depths. Plasma deposition rate was the smallest for 100% ethylene and increased by three to four fold when ammonia was added to the monomer mixture. The polymer coatings were of uniform thickness and exhibited a complex crosslinked structure. The 100% ethylene plasma polymer was strongly hydrocarbon in nature but had some oxygen and nitrogen containing groups. Plasma polymers from ethylene/ammonia mixture were much more polar and contained reactive and polar group constituents, including carbonyl, ether, primary and secondary amines, and hydroxyl groups. The presence of oxygen and nitrogen functionalities is presumed to arise primarily from the reaction of trapped radicals with oxygen and nitrogen when exposed to air. Small amounts of silicon were also detected in the plasma formed films.