Effect of Ar+ ion beam in the process of plasma surface modification of PET films

In general, plasma modified polymer surfaces tend to show short aging time and rapid hydrophobic recovery after treatment. To prevent reorientation from the surface to the bulk, appropriate crosslinking is necessary among the polymer chains. In this work, an Ar⁺ ion beam was used to provide crosslinking to the surface. Crosslinking was shown by spectroscopic ellipsometry, AFM, and FTIR. Contact angle measurements were performed to see the aging of the modified surfaces. The surface modified with Ar⁺ ion beam followed by RF plasma treatment exhibited reduced chain mobility and a highly stable hydrophilic surface. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1679–1683, 2000     

Focused ion beam patterning of diamondlike carbon films

For applications of diamondlike carbon films in optics, microelectronics and other fields, it is in some cases necessary to form submicron size patterns. A finely focused beam of 50 keV Ga⁺ ions was used to mill various patterns in amorphous carbon films prepared by a pulsed cathodic arc discharge method. The trenches with width down to 30 nm and depth-to-width ratios up to 25 have been milled. The minimum trench width down to 20 nm has been achieved. The nanotips with a radius down to 35–40 nm were fabricated. The influence of the focused ion beam parameters on the film's surface modification as well as on the shape of fabricated pattern elements is discussed.     

Effects of ion beam processing parameters on the adherence of DLC films

Scratch testing of hydrogenated DLC films applied via an energetic ion beam is used to demonstrate that critical failure loads are increased primarily by increasing a Si bond layer thickness. These loads also increase as DLC layer thickness is increased to a few micrometers and as ion energy is reduced below ca 500 eV. Processing temperatures <200°C have a negligible effect on the loads.     

Surface modification of polyimide and polysulfone membranes by ion beam for gas separation

The surface carbonization of polyimide (PI) and polysulfone (PSf) by ion beam has been performed to adapt the carbon molecular sieve properties on the skin of the polymeric membranes without the deformation of the membrane structure. In order to control the structure of membrane skin and to improve gas transport properties, the irradiation conditions, such as the dosage and the source of ion beams, have been varied. The ideal separation factor of CO₂ over N₂ through the surface‐modified PI and PSf membranes increased threefold compared to those of the untreated, pristine membranes, whereas the permeability decreased with almost two orders of magnitude. This appears to be due to the fact that the structure of membrane skin has been changed to a barrier layer. The formation of barrier layer was confirmed by comparing the calculated values of a simple resistance model with the experimental results, and the estimated permeability of this barrier was 10⁻⁴ barrer. It was concluded that ion beam irradiation could provide a useful tool for improving selectivity for gas separation membranes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1554–1560, 2000     

Surface modification of coil coatings with thin plasma polymer films structure and stability

Plasma deposition of a thin top layer with tailored properties is an effective strategy of modification of the organic coating surface. Thin plasma polymer layers are candidates and can provide superior hardness, scratch resistance, modified surface hydrophobicity and easy to clean properties.The present work studies the stability of thin plasma polymer films deposited as top layer on polyurethane coil coating systems. Microwave, hollow cathode and radio frequency plasma polymerization reactors were employed in order to deposit a thin SiO_x based plasma polymer layer.The plasma film stability was studied using surface analysis techniques, ex situ and in situ atomic force microscopy and scanning electron microscopy. Energy dispersive spectroscopy, FTIR spectroscopy and optical measurements confirm the composition and plasma layer properties. The structure of the plasma layers was investigated by means of transmission electron microscopy.The surface morphology together with composition evolution allows the study of the stability of the different coatings. The structure examination of the formed plasma polymer film offers good clarification for coating failure. Decrease of the operating pressure during plasma polymerization and oxygen concentration in precursor mixture lead to formation of compacter layer with higher stability. Introduction of fluorine-containing precursor also increases the anti-weathering performance of the plasma polymer films.     

离子束增强沉积制备p-ZnO薄膜

采用离子束增强沉积技术制备了ZnO薄膜,分析了退火温度、退火气氛对所制备ZnO薄膜的结构、电学特性和发光特性的影响。利用IBED法获得的薄膜p型N-In共掺ZnO薄膜在氮气下退火,随着退火温度的升高,薄膜电阻值先降低后升高,然后再降低。而在氧气下退火,即使退火温度只有400℃,薄膜的电阻很快变大。     

Moving ion fronts in mixed ionic‐electronic conducting polymer films

The aim of this paper is to analyze moving front dynamics of ions and holes in a planar, mixed ionic‐electronic conducting polymer film. As cations invade the film, holes evacuate; thus, an ionic current is converted to an electronic signal. Recent experiments show that the location of the advancing ion front increases as the square‐root of time, a scaling typically associated with diffusive transport, which is surprising given the large driving voltages utilized. Ionic and electronic transport is modeled via the drift‐diffusion equations. A similarity transformation reduces the governing partial differential equations to ordinary differential equations that are solved numerically. The similarity transformation elucidates the origin of the square‐root‐of‐time front scaling. The similarity solution is then compared to the numerical solution of the full drift‐diffusion equations, finding excellent agreement. When compared with experimental data, our model captures the front location; however, qualitative differences between the ion profiles are observed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1447–1454, 2015     

Synthesis of cobalt/diamond-like carbon thin films by biased target ion beam deposition

Cobalt/diamond-like carbon (Co/DLC) composite thin films were synthesized on silicon wafers by biased target ion beam deposition (BTIBD) in which Co was deposited by sputtering a negatively biased Co target using an Ar ion beam and DLC was produced simultaneously by a second ion beam with CH₄ as carbon source. The surface morphology, chemical composition and binding states of the synthesised thin films were studied. The as-deposited Co/DLC films are continuous and smooth with a thickness of approximately 150 nm for an hour of deposition. The average roughness is 3.5 ± 0.3 Å and the root-mean squared roughness is 5.3 ± 1.1 Å. The films are low in contaminations and the mass concentration of Co is approximately 24%. Fourier transform infrared spectroscopy and Raman spectroscopy results indicate the Co did not react with C and barely changed the microstructure of DLC. X-ray photoelectron spectroscopy and synchrotron based near-edge X-ray absorption fine structure studies indicate that the Co is in metallic form in the as-deposited films. The preliminary results demonstrate the promise to synthesize high quality Co/DLC composite films by BTIBD.     

A new possibility for microstructural investigation of clay-based polymer nanocomposite by focused ion beam tomography

This article describes the focused ion beam (FIB)-tomography as a high-resolution three-dimensional (3D) technique to study the morphology of polymer/clay nanocomposites. To establish the structure-property relationship of such composite material, it is very important to visualize the 3D-structure and distribution of clay particles in the polymer matrix. The sequential two-dimensional sectioning by FIB, followed by imaging of dispersed silicate layers using high-resolution scanning electron microscope, and computer reconstruction can show the degree of dispersion of silicate layers in 3D-space.     

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     

Mechanical properties and thermal stability of SiBCN films prepared by ion beam assisted sputter deposition

The high hardness, exceptional high temperature stability, and oxidation resistance of bulk Si–B–C–N ceramics have led to the expectation that these materials will be good candidates for superior coating materials in high-temperature applications. In this study, SiBCN films were prepared using ion beam assisted sputter (IBAS) deposition, and the mechanical properties and thermal stabilities of the films at 600, 700, and 800 °C in air were investigated. In particular, the effects of the ion beam assist on the properties of the SiBCN films were examined. The SiBCN films were deposited on Si plates by sputtering a target composed of Si + BN + C using a 2-keV Ar⁺ ion beam. A low-energy N₂⁺ and Ar⁺ mixed ion beam irradiated the samples during the sputter deposition. The Si content in the SiBCN films was controlled by changing the Si/(BN + C) ratio of the target. BCN films were also deposited for comparison. The composition and chemical bonding structure of the prepared films were investigated by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. We found that c-BN bonds were formed in the ion-assisted BCN film. The oxide layer thickness on the SiBCN films after thermal annealing decreased due to the IBAS deposition and an increase in the Si content. Ion-assisted SiBCN films annealed at 800 °C showed the highest hardness of 20 GPa.     

The influence of ion beam assisted deposition parameters on the properties of boron nitride thin films

We studied ion beam assisted deposition of cubic boron nitride thin films on silicon (100) and high speed steel. The boron nitride films were grown by the electron beam evaporation of pure boron (99.4%) and the simultaneous ion bombardment of a mixture of nitrogen and argon ions from a Kaufman ion source. At a constant boron evaporation rate, the ion energy, ion current density, substrate temperature and process gas mixture was varied. The thickness of the films was kept between 200 and 300 nm. Boron nitride films with >80% of the cubic phase (determined by Fourier transform infrared spectroscopy) were obtained with nitrogen/argon mixtures of 50/50 at ion energies of 450 eV and substrate temperatures of 400°C. The current density amounted to 0.45 mA cm⁻² at a nominal boron rate of 200 pm s⁻¹. Cubic boron nitride films were deposited on high speed steel by introducing a titanium interlayer for adhesion improvement.     

Epoxy polymer modification with metals

The modification of epoxy polymers with some metal cations, viz., Zn²⁺, Fe³⁺ and Mn⁴⁺, has been studied. These cations were introduced into the epoxy matrices by hardening of diglycidyl ether of bisphenon-A with the chelates of the metal salts with some aliphatic amines. Studies center on the dependence of the mechanical strength and heat resistance of the metal containing epoxy polymers with Zn²⁺ and Fe³⁺ increases the strength and heat resistance significantly. These metal-containing hardeners have excellent processability and can be used to produce high strength and high thermal resistance thermosets.     

聚合物表面紫外光接枝改性的研究

介绍聚合物表面紫外光接枝改性的研究方法,其中包括液相和气相接枝、接枝反应的引发方式及其机理,溶剂的影响和选择,针对不同改性要求对接枝单体的使用以及连续化操作的发展。此外,还简要介绍了聚合物表面接枝效果的测试方法和接枝后表面形态的观测方法     

聚合物氟化改性的研究进展

对聚合物的氟化改性的研究方法、含氟聚合物的性能研究及其应用前景进行了综述,并预测了其发展方向。     

硫磺聚合物水泥的橡胶改性

硫磺聚合物混凝土/砂浆是一种采用改性硫磺作为粘结剂的高性能复合材料,其主要特点是强度高、吸水性低、固化迅速和耐酸碱性良好.本试验的目的是研究废轮胎橡胶在改性硫磺砂浆中作为增韧剂和防开裂稳定剂的可能性.研究了橡胶改性硫磺砂浆的机械性能并将其与波特兰水泥砂浆进行了比较.     

Electron beam curing of polymer composites

Electron‐beam (E‐Beam) curing of an epoxy polymer matrix and its composite (reinforced with IM7 Carbon fibers) was studied using a cationic photoinitiator. Photoinitiator concentration, dose, and process temperature were varied to understand their influence on E‐beam curing. Optimal photoinitiator concentration was found to be 5 phr. The curing was due to a primary α reaction with a strong dependence on dose, and a secondary β reaction with a weak dependence on dose and a strong dependence on initiator concentration. The extent of cure increased rapidly with dose until 100 kGy and it approached a plateau value beyond 100 kGy. This plateau value corresponded to incomplete curing by 27% for resin and 22% for composite at a process‐temperature of 22°C. The causes for incomplete curing appear to be the secondary β reaction and diffusional limitation. Increase in process temperature resulted in higher extent of cure at a dose level. The material used in this study was also found to be thermally curable and the reaction onset temperature (measured in a DSC ramp experiment) reduced from about 150°C at 0 kGy to about 50°C at 30 kGy. This indicates that simultaneous thermal curing during E‐beam curing of resin and composite is possible. After thermal post‐curing, the T_g of the E‐beam cured resin increased from 130°C at 200 kGy to a value greater than 370°C and the modulus decreased by 10%. The service temperature and the modulus of the 100% thermally cured resin and the thermally post‐cured (after E‐Beam irradiation) resin were comparable.     

Rheology of solvent-cast polymer films

This paper describes and analyzes the results of an experiment where various thin polymeric films are continuously sheared between smooth glass substrates. The shear force per unit area has been measured as a function of mean uniaxial stress and temperature using representative “good” and “poor” casting solvents followed by a range of heat treatments. The polymers studied include high density polyethylene, polybisphenol-A–carbonate, poly(ethylene terephthalate), atactic polystyrene, isotactic polystyrene, atactic poly(methyl methacrylate), isotactic poly(methyl methacrylate), poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl pyrrolidone), poly(vinyl chloride), and polytetrafluoroethylene. The results indicate that the casting solvent has a very pronounced influence upon the rheology of the film. The casting solvents may apparently confer either ductile or brittle failure in the film and also influence the nature of the temperature and pressure dependence of the shear stress. The data have been analyzed using Eyring theory and also by reference to relevant published literature on the influence of solvent and thermal treatments on the morphology and deformation behavior of polymers. “Good” solvents generally tend to promote a brittle mode of failure with little temperature dependence. The same type of solvents also produced films which have higher shear strengths and show greater increases in shear strength with pressure. These data are adequately rationalized using free volume and entanglement notions.     

TiO2 nanoceramic films prepared by ion beam assisted evaporation for optical application

A TiO₂ nanoceramic film was prepared as an alternative absorber layer for infrared thermal detectors. The TiO₂ film was amorphous, and its grain size increased with the ion anode voltage and oxygen flow rate. Moiré deflectometry was applied for measuring the nonlinear refractive indices of TiO₂ films on polycarbonate (PC) substrates. The nonlinear refraction index was measured to be of the order of 10⁻⁸ cm² W⁻¹ and the change in refractive index was of the order of 10⁻⁵. The linear refractive index was correlated with the porosity. Denser TiO₂ films exhibited higher linear refractive indices, obvious red-shifts and narrower absorption bands in the near-IR region.