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     

Size‐dependent optical properties of transparent,spin‐coated polystyrene/ZnO nanocomposite films

Zinc oxide (ZnO) nanoparticles are synthesized using a simple chemical method at room temperature. A variation in molar concentration of the precursor, potassium hydroxide, from 0.25 to 0.01 mol L^?1 is accompanied by a decrease in the average size of the nanoparticles. These nanoparticles are used for the preparation of polystyrene/ZnO nanocomposite films using the spin‐coating technique. These films are found to be highly transparent throughout the visible region and absorb UV light in the region from 395 to190 nm, almost covering the near and middle UV ranges (400 to 200 nm). This observation highlights the possible prospects of these films in UV shielding applications. The wavelength corresponding to the onset of UV absorption is found to be blue shifted with a decrease in size of the ZnO particles in the composite films due to confinement effects. The photoluminescence spectra of the composite films also change as a function of particle size. The emissions at longer wavelength due to defects and impurity‐related states in ZnO are almost quenched as a result of surface modification by the polymer matrix. The observed band‐gap enlargement with a decrease in size of the ZnO particles in the composite films is significant for band‐gap engineering of nanoparticles for various applications. Copyright © 2011 Society of Chemical Industry     

Exceptionally good,transparent and flexible FeS2/poly(vinyl pyrrolidone) and FeS2/poly(vinyl alcohol) nanocomposite thin films with excellent UV‐shielding properties

Composites of nanocrystalline iron disulfide (FeS₂) coated with poly(vinyl pyrrolidone) (PVP) or poly(vinyl alcohol) (PVA) have been successfully synthesized using a solvothermal process, in which PVP and PVA serve as soft templates. Transparent, flexible thin films of these nanocomposites were prepared from homogeneous solution using a solution‐casting approach. X‐ray diffraction and thermogravimetric analysis and energy‐dispersive X‐ray, Fourier transform infrared and UV‐visible absorption spectroscopic techniques were employed to study the structural and optical properties of these nanocomposite films. UV‐visible spectra in transmission mode reveal the UV‐shielding efficiency of these nanocomposite films and the films are found to be exceptionally good for UV‐shielding applications in the wavelength range 200 to 400 nm. The present work aims at developing transparent and flexible UV‐shielding materials and colour filters using cost‐effective and non‐toxic inorganic–polymer nanocomposites. © 2012 Society of Chemical Industry     

Hydrophilic–oleophobic behaviour in thin films from fluoromodified nanoclays and polystyrene

New nanocomposite thin films were prepared by spin coating technique from polystyrene (PS) and montmorillonite (MMT) modified with perfluoropolyether cationic ammonium salts (FOMMT). The coating thickness was tuned by changing the solution concentration, and it was measured by the scratching method with atomic force microscopy (AFM). Demodulation AFM images of the higher thickness (>100 nm) PS/FOMMT nanocomposite coating do not show any phase difference suggesting the formation of a homogeneous structure, while the corresponding demodulation image of the lower thickness (ca. 60 nm) PS/FOMMT nanocomposite film revealed the presence of two different phases, which may be attributed to fluoromodified clays and polystyrene. Surface characterization was made through contact angle (CA) measurements and it showed unexpectedly low surface tension dispersive component γ _s ^d (around 12 mN/m) and a very high polar components γ _s ^d (50 mN/m) in the case of the lower thickness PS/FOMMT nanocomposite coating.     

Multilayer polyimide nanocomposite films synthesis process optimization impact on nanoparticles dispersion and their dielectric performance

The preparation of polyimide (PI)/nanocomposite films and their thickness are a complex process with some ambiguous variables that are involved in the synthesis process. Therefore, it is crucial to understand those variables and reveal the chemistry behind them. Several methods have been probed until an optimal synthesis process was found. A detailed synthesis process optimization is described in this article to understand all variables, which can influence the molecular weight of polyamic acide (PAA) solution, the thickness of films, and nanoparticles dispersion. The spin coating technique was used to control the thickness of single and multilayer PI/nanocomposite films, which reveals that the thickness of the casted PI film depends on several factors, such as the viscosity, molecular weight of the PAA solution, and the spin speed of spin coater. Factors, which can influence the molecular weight of PAA solution, are discussed in detail. After completing the synthesis process, the single and multilayer PI nanocomposite films are characterized experimentally. The results reveal that using a thin layer of nanocomposite on PI film in the form of a multilayer structure improves the nanoparticles dispersion and thereafter its dielectric properties.     

Preparation and properties of poly(propylene carbonate) and nanosized ZnO composite films for packaging applications

A series of polypropylene carbonate (PPC)/ZnO nanocomposite films with different ZnO contents were prepared via a solution blending method. The morphological structures, thermal properties, oxygen permeability, water sorption, and antibacterial properties of the films were investigated as a function of ZnO concentration. While all of the composite films with less than 5 wt % ZnO exhibited good dispersion of ZnO in the PPC matrix, FTIR and SEM results revealed that solution blending did not lead to a strong interaction between PPC and unmodified ZnO. As such, poor dispersion was induced in the composite films with a high ZnO content. By incorporating inorganic ZnO filler nanoparticles, the diffusion coefficient, water uptake in equilibrium, and oxygen permeability decreased as the content of ZnO increased. The PPC/ZnO nanocomposite films also displayed a good inhibitory effect on the growth of bacteria in the antimicrobial analysis. The enhancement in the physical properties achieved by incorporating ZnO is advantageous in packaging applications, where antimicrobial and environmental‐friendly properties, as well as good water and oxygen barrier characteristics are required. Furthermore, UV light below ～ 350 nm can be efficiently absorbed by incorporating ZnO nanoparticles into a PPC matrix. ZnO nanoparticles can also improve the weatherability of a PPC film. In future research, the compatibility and dispersion of the PPC matrix polymer and the inorganic ZnO filler nanoparticles should be increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Transparent and thermally stable improved poly (vinyl alcohol)/Cloisite Na/ZnO hybrid nanocomposite films: Fabrication,morphology and surface properties

A series of poly(vinyl alcohol)/Cloisite Na⁺-Tyrosine/Zinc oxide (PVA/Cloisite Na⁺-Tyr/ZnO) bionanocomposites were prepared by dispersing ZnO nanoparticles in solution containing mixture of the PVA and modified Cloisite Na⁺. Structure of nanocomposite coatings was investigated by X-ray diffraction and Fourier-transform infrared spectroscopy. The thermal stability and optical properties of bionanocomposite were characterized by thermogravimetric analysis and UV–vis spectroscopy, respectively. The introduction of ZnO nanoparticles into PVA/Cloisite Na⁺-Tyr mixed solutions significantly increased the thermal stability of the obtained films. The results revealed that the high UV-shielding efficiency of the composites: for a film containing 6.0 wt% of ZnO nanocrystals, over 92% of UV light at wavelengths of 368 nm was absorbed while the optical transparency in the visible region was slightly below that of a PVA/Cloisite Na⁺-Tyr film.     

Synthesis and characterizations of magnetite nanocomposite films for radiation shielding

Polyvinyl alcohol (PVA) films containing magnetite Fe₃O₄ nanoparticles have been prepared by co‐precipitation method for use in gamma ray shielding and protection. Characterizations of the magnetite/PVA nanocomposite films were investigated by X‐ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, and magnetization measurements. TEM images showed that the synthesized magnetite particles had about 6–11 nm dimensions. Optical study's results revealed that the optical energy band gaps of thin films range between 1.82 and 2.81 eV at room temperature using UV–visible absorption spectroscopy. The saturation magnetization (MS) value measured by vibrating sample magnetometer VSM was found to be 8.1 emu/g with superparamagnetic nature. The radiation shielding properties such as linear attenuation coefficients (μ ) and half‐value thickness (HVT) for the magnetite nanocomposite films have been obtained experimentally for different photon energies. The results imply that these nanocomposites films are promising radiation shielding materials. POLYM. COMPOS., 38:974–980, 2017. © 2015 Society of Plastics Engineers     

Poly(caprolactone) thin film preparation,morphology, and surface texture

The properties and surface uniformity of poly‐ (caprolactone) (PCL) thin films were measured. Thin films were prepared using a spin‐coating technique. Film thickness and roughness were correlated with variation in solution concentration, spinning speed and spinning time. Differential scanning calorimetry (DSC) was used to investigate the crystallization and melting processes. The enthalpy of melting variation correlated with the film thickness, while melting temperature was independent of film thickness. In addition, surface roughness was found to be a function of PCL thickness. Film thickness and roughness showed a progressive decrease when spinning speed was increased, while spinning time provided no significant influence on film thickness. PCL thickness and roughness significantly increased when PCL solution concentration increased. Hot stage optical microscopy showed that larger spherulitic crystals were present in thin films, and the smaller crystals present in thicker films had a coarser texture consistent with increased surface roughness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1287–1294, 2007     

Pea starch‐based composite films with pea hull fibers and pea hull fiber‐derived nanowhiskers

New applications of both pea hull fiber (PHF) and PHF‐derived nanowhiskers (PHFNW), isolated from PHF by acid‐hydrolysis, as fillers in starch‐based biocomposite films were explored in this work. Two series of films were prepared by blending pea starch (PS), respectively, with PHF and PHFNW. The effects of PHF and PHFNW as filler on the structure and properties of the composite films were comparatively investigated by observation of morphology and analysis of thermal, optical, and mechanical properties. The results revealed that the PS/PHFNW nanocomposite films exhibited improved physical properties over both the neat PS film and PS/PHF microcomposite films. The light transmittance at 800 nm, tensile strength, elongation at break, and Young's modulus were 56.0%, 4.1 MPa (Megapascal), 30.1%, 40.3 MPa, respectively, for the PS film without filler; 58.0%, 7.6 MPa, 41.8%, and 415.2 MPa for the PS/PHFNW film containing 10 wt% filler; and 37.2%, 2.8 MPa, 17.0%, and 29.8 MPa for the PS/PHF film containing 10 wt% filler. The improvement to the properties of PS/PHFNW nanocomposite films may be attributed to the nanometer size effect of PHFNW, which resulted in the homogeneous dispersion of PHFNW within the PS, and the strong interactions between the matrix and the nanoscale filler. POLYM. ENG. SCI., 2009. Published by the Society of Plastics Engineers     

Chemical solution deposition of pure and Gd-doped ceria thin films: Structural,morphological and optical properties

High quality smooth, uniform and crack-free ceria and gadolinium doped ceria (GDC) thin films were prepared on Si and Si/YSZ substrates by chemical solution deposition. The thermal behavior of Gd-Ce-O precursor was investigated by TG-DSC measurements. The phase purity and structure of deposited films were evaluated using X-ray diffraction (XRD) analysis and Raman spectroscopy. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed for the estimation of surface morphological features. Oxidation state of Ce ions in fabricated films was analyzed by X-ray photoelectron spectroscopy (XPS). Optical properties were evaluated by diffuse reflectance UV–vis spectrometry. Thickness of the films can be controlled by applying a certain number of spin coating cycles. A linear relation between the thickness of the films and the number of deposited layers was observed. The single-layer thickness was determined to be approximately 20 nm. The influence of annealing temperature and Gd content on the film structure, morphology and optical properties was studied and discussed. The dependence of an optical band gap as a function of grain size was demonstrated.     

Spin and dip coating of light-emitting polymer solutions: Matching experiment with modelling

This paper reports experimental observations on spin and dip coating of light-emitting polymer (LEP) solutions where both the process conditions as well as the solution properties are factors influencing thickness and uniformity of thin LEP films. In terms of spin coating, which is a typical process for the manufacture of polymer light-emitting diodes (PLEDs), a number of process variables including spin speed were systematically explored. A matching series of dip-coating experiments was also carried out with the retraction speed as a primary variable. Modifications of existing models for both spin and dip coating were developed to include solvent evaporation and the effect of solution viscosity change during evaporation. Both models were found to give reasonable agreement with the major observed trends for final film thickness as a function of process conditions tested in this paper.     

Preparation of highly emissive,thermally stable,UV‐cured polysilsesquioxane/ZnO nanoparticle composites

A high molecular weight polysilsesquioxane (LPMSQ)/ZnO nanocomposite was prepared by blending a methacryl‐substituted polysilsesquioxane and PMMA‐coated ZnO nanoparticle (NP) followed by UV‐curing process. These LPMSQ/ZnO nanocomposites gave high thermal and mechanical stabilities originated from the rigid ladder structured siloxane backbone of LPMSQ. The polysilsesquioxane and surface‐modified ZnO nanoparticles showed excellent compatibility between MMA groups in LPMSQ‐ and PMMA‐capped ZnO nanoparticles to give well‐dispersed LPMSQ/ZnO nanocomposites. Mechanically pliant and flexible free standing films were obtained, and the photo and optical properties of these hybrid nanocomposites were examined. The high photoluminescent properties were maintained even after severe thermal treatments exceeding 400°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42333.     

紫外光固化腰果酚/ZnO复合膜的性能研究

将紫外光固化技术与溶胶-凝胶法相结合,制备了紫外光固化腰果酚/ZnO复合涂料;研究了ZnO在复合膜中的分散状态,以及ZnO含量对复合膜的热稳定性、抗紫外线性能、常规物理机械性能、抗溶剂性和耐化学介质性能的影响。结果表明,当ZnO含量不超过3%时,其以纳米尺寸均匀分布于复合膜中;随着ZnO纳米粒子含量的增加,复合膜的热稳定性、抗紫外线性能、抗溶剂性、硬度和抗冲击强度逐渐增大,光泽度、附着力、柔韧性和耐化学介质性能受ZnO含量的影响不大。     

Preparation and characterization of poly(styrene butylacrylate) latex/nano‐ZnO nanocomposites

Poly(styrene butylacrylate) latex/nano‐ZnO composites were prepared by blending poly(styrene butylacrylate) latex with a water slurry of nano‐ZnO particles, and the effects of certain parameters, such as particle size, dispersant type, dispersing time and others, on the dispersibility, mechanical properties, ultraviolet (UV) shielding and near infrared (NIR) shielding were investigated with transmission electron microscopy (TEM), an Instron testing machine, dynamic mechanical analysis and ultraviolet‐visible‐near infrared (UV‐VIS‐NIR) spectrophotometry. TEM observation showed that dispersants with long chains are better than those with short chains at enhancing the dispersibility of nano‐ZnO particles in a matrix; extending dispersing time also improves the dispersibility of nano‐ZnO particles in a matrix. Instron tests showed that the nanocomposite polymers embedded with nano‐ZnO particles had much higher tensile strength than the corresponding composite polymers with micro‐ZnO particles. As the nano‐ZnO content increased, the temperature of glass transition (T_g) of the nanocomposite polymer embedded with 60 nm ZnO particles first increased then decreased, but 100 nm ZnO and micro‐ZnO particles seemed to have no influence on the T_g of the composite polymers. The better dispersibility of nano‐ZnO particles resulted in higher T_g values. Increasing nano‐ZnO content or dispersibility could enhance the UV shielding properties of the nanocomposite polymers, and 60 nm ZnO particles could more effectively shield UV rays than 100 nm ZnO particles. Micro‐ZnO particles basically had no effect on the UV absorbance of the composite polymers. A blue‐shift phenomenon was observed at 365 nm when nano‐ZnO particles were present in the nanocomposite polymers. NIR analysis indicated that as nano‐ZnO content increased, the NIR shielding of the nanocomposite polymers increased, but the NIR shielding properties seemed to be more influenced by particle size than by the nano‐effect. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1923–1931, 2003     

Electrochemical synthesis and in situ spectroelectrochemistry of conducting polymer nanocomposites. I. polyaniline/TiO2, polyaniline/ZnO,and polyaniline/TiO2+ZnO

The polyaniline (PAn), polyaniline/titanium dioxide (PAn/TiO₂), polyaniline/zinc oxide (PAn/ZnO), and a novel conducting polymer nanocomposites, polyaniline/titanium dioxide + zinc oxide (PAn/TiO₂+ZnO), were synthesized by in situ electropolymerization and potential cycling on gold electrode. The PAn and nanocomposite films were characterized by cyclic voltammetry, Fourier transform infra‐red (FTIR) spectroscopy, in situ resistivity measurements, in situ UV–Visible, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between cathodic and anodic peaks of three redox couples were obtained for PAn and polymeric nanocomposite films. During cathodic and anodic scans, the shift of potential was observed for polymer nanocomposite films. The characteristic FTIR peaks of PAn were found to shift to lower wavelengthsin polymer nanocomposite films. These observed effects have been attributed to interaction of TiO₂, ZnO, and TiO₂+ZnO particles with PAn molecular chains. Significant differences from in situ resistivity of PAn and nanocomposite films were obtained. The resistance of PAn/TiO₂, PAn/ZnO, and PAn/TiO₂+ZnO films were found to be smaller than the PAn film. The in situ UV–Visible spectra for Pan and polymer nanocomposite films were studied. The results show the intermediate spectroscopic properties between PAn and polymer nanocomposite films. The morphological analyses of PAn and nanocomposite films have been investigated. The nanocomposites SEM and TEM micrographs suggest that the inorganic semiconductor particles were incorporated in organic conducting polymer, which consequently modifies the morphology of the films significantly. POLYM. COMPOS., 35:351–363, 2014. © 2013 Society of Plastics Engineers     

UVA‐shielding silicone/zinc oxide nanocomposite coating for automobile windows

Among all types of ultraviolet radiation, UVA rays are the most prevalent and can penetrate clouds and glass. In this article, we report the fabrication of a novel silicone/zinc oxide (ZnO) nanocomposite that has outstanding performance in shielding the harmful UVA light. We prepared wurtzite ZnO nanoparticles of three growth durations and dispersed them in a transparent silicone matrix via solution mixing. Our results exhibit a red shift in the absorption peak of the nanocomposites when compared with ZnO colloidal dispersions and decreasing the growth duration of ZnO nanoparticles could improve the UVA‐shielding properties of the nanocomposite. In addition, the nanocomposite presents good shear adhesion strength over 10.5 MPa on glass substrate. The excellent optical and mechanical properties of the novel nanocomposite make it highly promising for automobile window coatings. POLYM. COMPOS., 37:2053–2057, 2016. © 2015 Society of Plastics Engineers     

Electrical and Electromagnetic Interference (EMI) shielding properties of hexagonal boron nitride nanoparticles reinforced polyvinylidene fluoride nanocomposite films

The hexagonal boron nitride nanoparticles (h-BNNPs) reinforced flexible polyvinylidene fluoride (PVDF) nanocomposite films were prepared via a simple and versatile solution casting method. The morphological, thermal and electrical properties of h-BNNPs/PVDF nanocomposite films were elucidated. The electromagnetic interference (EMI) shielding properties of prepared nanocomposite films were investigated in the X-band frequency regime (8–12 GHz). The EMI shielding effectiveness (SE) was increased from 1 dB for the PVDF film to 11.21 dB for the h-BNNPs/PVDF nanocomposite film containing 25 wt% h-BNNPs loading. The results suggest that h-BNNPs/PVDF nanocomposite films can be used as lightweight and low-cost EMI shielding materials.     

Optical and physical properties of zirconium dioxide reinforced poly(methyl methacrylate) nanocomposite films

The objective of this study was to investigate the fundamental aspects of acrylic resin and zirconia nanoparticle interaction to analyze the optical properties and subsequent changes in refractive index with incremental loading of nanoparticles. Poly(methyl methacrylate) (PMMA) reinforced with zirconia nanoparticles were prepared by dip coating, spin coating and solvent casting techniques. An overall understanding of the polymer nanocomposite film has been achieved using the spectroscopic and morphological studies. The vital aspect of this whole study is to derive a simple yet an efficient nanocomposite film capable of imparting extraordinary optical properties. Within the limitations of this research a very crucial property of the material has been revealed. The RI as well as the optical transparency of the nanocomposite film has been steadily maintained with a significant increase of RI by the magnitude of 0.06 and ~100% light transmittance on incorporation of pure zirconia nanoparticles into PMMA matrix has been achieved. The best technique found was spin coating as it could yield thin films and better transparency and higher refractive index.     

Striation-Free, Spin-Coated Sol-Gel Optical Films

A process for eliminating surface striations in optical films prepared by sol-gel spin coating is described. The surface morphology of Nd-doped SiO₂-TiO₂ films, codoped with phosphorus, was investigated, using stylus profilometry, ellipsometry, and reflective optical microscopy. Compared to the conventional spin coating technique, the new process, where a saturated ethanol atmosphere is created over the spinning substrate, leads to a very low surface roughness, but to the same refractive index value. The thickness of uniform thin films prepared by this process is about half that of films made by the conventional method, at any spinning rate and for any given solution aging time.