Surface tailoring of an ethylene propylene diene elastomeric terpolymer via plasma‐polymerized coating of tetramethyldisiloxane

In the research presented here, we explore the use of a low‐energy plasma to deposit thin silicone polymer films using tetramethyldisiloxane (TMDSO) (H(CH₃)₂? Si? O? Si? (CH₃)₂H) on the surface of an ethylene propylene diene elastomeric terpolymer (EPDM) in order to enhance the surface hydrophobicity, lower the surface energy and improve the degradation/wear characteristics. The processing conditions were varied over a wide range of treatment times and discharge powers to control the physical characteristics, thickness, morphology and chemical structure of the plasma polymer films. Scanning electron microscopy (SEM) shows that pore‐free homogeneous plasma polymer thin films of granular microstructure composed of small grains are formed and that the morphology of the granular structure depends on the plasma processing conditions, such as plasma power and time of deposition. The thicknesses of the coatings were determined using SEM, which confirmed that the thicknesses of the deposited plasma‐polymer films could be precisely controlled by the plasma parameters. The kinetics of plasma‐polymer film deposition were also evaluated. Contact angle measurements of different solvent droplets on the coatings were used to calculate the surface energies of the coatings. These coatings appeared to be hydrophobic and had low surface energies. X‐ray photoelectron spectroscopy (XPS) and photoacoustic Fourier‐transform infrared (PA‐FT‐IR) spectroscopy were used to investigate the detailed chemical structures of the deposited films. The optimum plasma processing conditions to achieve the desired thin plasma polymer coatings are discussed in the light of the chemistry that takes place at the interfaces. Copyright © 2004 Society of Chemical Industry     

等离子体浸没式离子注入-离子束增强沉积TiN膜研究

本文采用一种新型的等离子体浸没式离子注入 离子束增强沉积的技术(PIII IBAD),在Cr12MoV钢基体上制备出了TiN膜,对沉积膜的组织进行了光电子能谱分析,并对沉积膜进行了硬度检测、摩擦试验及磨痕形貌分析。试验结果表明,沉积膜中的组织为TiN、TiO2和Ti2O3,TiN膜具有高达Hv3200的高硬度和极其优良的摩擦性能。     

氧化锌颗粒膜电阻响应-恢复特性研究

测试了氧化锌颗粒膜电阻响应-恢复特性，讨论了颗粒形态，加热电压、环境气氛、气氛浓度和注入方式等因素对电阻响应-恢复特性的影响。结果表明，随着加热电压的升高，电阻响应-恢复的速度和程度明显加大；断续注入时颗粒膜电阻值的响应随着浓度的增加逐步减弱．     

Influence of the deposition atmosphere on the characteristics of Pd–Mg thin films prepared by pulsed laser deposition

Bilayered palladium (30 nm thick)–magnesium (350 nm thick) thin films were prepared using the pulsed laser deposition technique in the presence of various background gases (Ar, He and a mixture He + H₂) under different partial pressures (47 and 27 Pa). According to the deposition atmosphere, the Pd/Mg interface shows either a sharp or an extended transition. The electrochemical hydriding properties and the mechanical stability upon cycling of the Pd/Mg film are greatly improved when an extended «intermixing» zone between the Pd and Mg layers is present. The Pd–Mg films prepared under pure helium fulfill these conditions.     

Thin film deposition on a corrugated surface: A molecular dynamics approach

This paper presents the use of molecular dynamics (MD) simulation in the investigation of the surface topography of early-stage film growth on a GMR (giant-magnetoresistance) corrugated structure. The size of the simulated system is limited in order to reduce the computational workload. The numerical model adopts the Morse potential and the Verlet-leapfrog time evolution scheme [R.W. Hockney, 1970; D. Potter, 1972 (Chapter 5). [1]] to describe the atomic interactions which take place between the atoms. The impact energy transferred from the incident atoms to the substrate is modeled by rescaling the atoms within the upper substrate layers. It is found that the important properties of the film-substrate system may be obtained after the deposition of just several atomic layers. The influence of the impact velocity upon the coating parameters is investigated by varying the incident energy of the deposited atoms. The current results indicate that the surface coverage is poor, when atoms are deposited at low incident energies upon a low temperature substrate. At a higher incident energy, the deposited film tends to exhibit a quasi-layer-by-layer growth mechanism, which results in an improved surface coverage. Finally, it is demonstrated that a distinct quasi-fluid behavior is evident on the substrate when the atoms are deposited at high incident energies.     

基于PTFE的PCB的多层层压方法

介绍了采用不同材料类型的粘结膜、半固化片、所需设备和粘结材料,用于生产低到高层数的PTFE多层板的情况。     

Effect of temperature on the optical and electro-optical properties of poly(methyl methacrylate)/E7 polymer-dispersed liquid crystal composites

Experiments on the effect of temperature on the optical and electro-optical behaviors of polymer-dispersed liquid crystals (PDLCs) are considered. Composite films composed of poly(methyl methacrylate) (PMMA) and the nematic-type liquid crystal (LC) E7 were prepared by solvent casting in chloroform. The PDLC film contained droplets of E7 from 10 to 80 wt % in a PMMA matrix. Morphological studies illustrated the formation of isolated droplets of LC due to phase separation, and their homogeneous distribution increased with increasing E7 content. Thermo-optical studies showed an increase in the nematic–isotropic transition temperature of composites, which indicated preferential solvation during the phase-separation process. The electro-optical characteristics were studied under the conditions of an externally applied square wave electric field with a He–Ne laser (λ = 632.8 nm) as a light source. The responses improved as the E7 content in PMMA increased. Semipermanent memory effects were noticed in composites at higher temperatures. Changes in the transmittance due to thermal variations provided the possibility of using such a device as a temperature sensor. The results obtained indicate that under these experimental conditions, the output can be controlled to the desired level by the selection of a suitable loading of LC to prepare PDLC electro-optically active composite films with a response time on the order of only a few milliseconds. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of polyaniline films using Fenton reagent

The chemical oxidation of aniline to form polyaniline (PANI) films and powder samples was made using Fenton reagent as an oxidizing agent in aqueous sulfuric acid medium. The PANI films were monitored by using the quartz crystal microbalance and the electronic absorption techniques. The optimum concentration was determined and the results were justified by measuring the UV–vis absorption spectra for the in situ PANI films. The conductivity for the PANI films and powder samples, prepared in different conditions, was measured. Also, the IR spectra, X‐ray and the thermogravimetric analysis for the PANI powder formed in the bulk were measured and compared with the polymer prepared using ammonium peroxydisulfate. A preliminary investigation to the dielectric properties of the polymer powder was measured and discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Structure and processability of iodinated poly(vinyl alcohol). IV. Drawability of the films iodinated at solution before casting

The drawability of iodinated at solution before casting (IBC) polyvinyl alcohol films prepared by casting aqueous solutions of 10 wt % PVA containing 15.2, 39.8, 83.2, 117.0, and 140.1% was examined with a tensile tester at 20–60°C. The tensile behavior of IBC films showed that the yield and breaking loads were much lower, and the breaking elongation was even higher than those of the unoriented iodinated after casting (IAC) films as well as the untreated PVA films. The maximum draw ratios of the films with the weight gain of 15.2, 39.8, 83.2, 117, and 140.1% were 4.5, 5.5, 8.5, 8.0, and 7.5, respectively, which were achieved at 20°C in all. The crystallinity of all films increased by the maximum draw, regardless of crystallinity before drawing. The crystalline structure was recovered to the original PVA crystalline lattice by deiodination. Amorphous orientation and initial moduli increased with the maximum draw ratio, while the orientation of crystals was constant. The orientation and moduli increased up to the weight gain of 83.2%, whose highest draw ratio and initial modulus were 8.5 and of 7.1 GPa, respectively, and then decreased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008