Simple fabrication of micro lens arrays

Microporous polymer films with a hexagonal arrangement of pores were prepared by simple casting of various polymer solutions under humid conditions. Hexagonally packed micropores were prepared by using condensed water droplets as templates on the surface of polymer solutions. Spherical micro lens arrays (MLAs) were fabricated simply by molding from the resulting honeycomb structures. By peeling off the upper layer with adhesive tape, the pillars were severed, forming pins on each layer, and a hexagonal array of pincushion structures was generated by this procedure. Hemispherical MLAs were also fabricated by molding the pincushion structures. The hemispherical MLAs projected clearer miniaturized images than spherical MLAs.     

Mesoscale pincushions, microrings, and microdots prepared by heating and peeling of self-organized honeycomb-patterned films deposited on a solid substrate

We describe here a preparation of pincushion structures with holes, hexagonally arranged microrings, and microdots by simple heating and peeling of self-organized honeycomb-patterned films. We have reported that the honeycomb-patterned films can be prepared by casting the solution of an amphiphilic polymer and a hydrophobic polymer under humid conditions. When annealing the honeycomb-patterned films prepared from an amphiphilic copolymer and poly(bisphenol A carbonate), we obtained a variety of mesoscale structures, depending on the heating temperatures. We revealed that these microstructures were formed by using the phase-separation structures in the self-organized honeycomb-patterned films. These micropatterns can be utilized for the template for microelectrodes, superhydrophobic surfaces, photonic crystals, and as a substrate for tissue engineering.     

Double-Layered Metal Mesh Film With Limited Viewing Angle Prepared by Electroless Plating of Self-Organized Honeycomb Film

We have reported that honeycomb-like porous polymer films, which were spontaneously formed in the casting of polymer solutions under humid conditions, were converted into honeycomb-like metal meshes by electroless plating. In this report, the unique optical properties of these meshes will be discussed. Silver-coated honeycomb mesh films were prepared by selforganization and electroless plating methods. The incident angle dependence of their transparency, and their electrical conductivity were measured. The metallized film had limited viewing angle.     

Fabrication of Ordered Arrays of Biodegradable Polymer Pincushions Using Self-Organized Honeycomb-Patterned Films

Nano- and micropatterned structures of tissue engineering scaffolds made of biodegradable and biocompatible polymers profoundly influence cell behavior. The present study describes a technically simple and inexpensive method to rapidly fabricate hexagonal arrays of biodegradable polymer pillars (pincushions). As precursors to these polymer pincushion arrays, highly regular porous biodegradable polymer films (self-organized honeycomb-patterned films, called honeycomb films) were prepared on a glass substrate using a simple casting technique. Scanning electron microscope observations revealed that the honeycomb film was composed of a top and bottom layer. This double-layered structure is attributable to the self-organization of hexagonally packed arrays of water droplets that form the template. When we peeled off the top layer of the honeycomb film under ambient conditions using adhesive tape, we obtained arrays of polymer pincushions on both side of the glass substrate and on the adhesive tape. Each air hole is surrounded by six pincushions, each with a diameter of 0.1-1 µm. We also studied factors that determine the morphology of the pincushions, such as the thermal and mechanical properties of the polymers used. It was shown that the heights, widths, and distances of separation between the pincushions could be controlled by the choice of polymer and the pore structure of the original honeycomb film. Such well-ordered, biologically inspired pincushion structures could find application in biomedical, photonic, and electronic materials.     

Superhydrophobic and lipophobic properties of self-organized honeycomb and pincushion structures

This report describes the simple preparation of superhydrophobic and lipophobic surfaces by self-organization. Microporous polymer films of a fluorinated polymer with hexagonally arranged pores were prepared by casting from solution under humid conditions. Hexagonally packed water microdroplets were formed by evaporative cooling on the surface of the casting solution. After solvent evaporation, a honeycomb-patterned polymer film was formed with the water droplet array acting as a template; the water droplets themselves evaporated soon after the solvent. Two porous polymer layers were stacked vertically, separated by pillars at the hexagon vertexes. After peeling off the top layer using adhesive tape, a pincushion-like structure was obtained. Here, we show that superhydrophobic behavior was achieved, with the maximum contact angle, 170 degrees, observed using these pincushion structures. Theoretical calculations fit the experimental results well. The lipophobic properties of the films are also discussed.     

陶瓷表面无敏化活化法微细化学镀铜

本文提出一种新的化学镀铜工艺,与激光微细刻蚀技术相结合可在Al2O3基底上实现无敏化活化化学镀铜,获得光亮致密、分辨率较高(40μm),导电性良好的化学镀层.     

溶剂散逸自组装制备导电各向异性的金属有序阵列

通过溶剂散逸自组装法制备了聚苯乙烯(PS)有序多孔膜. 利用水珠在冷的PS溶液表面凝结形成有序阵列, 使PS以水珠阵列为模板形成有序多孔膜. 将有序多孔膜的上层剥离并附着在可收缩性高分子表面, 并进行离子溅射, 除掉有序多孔膜后在可收缩膜上留下了有序的金属圆盘阵列. 经过收缩, 有序阵列不仅光学性质发生了改变, 而且实现了导电的各向异性.     

Effect of preparation methods on Pt/alumina catalysts for the hydrogen iodide catalytic decomposition

Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction,impregnation-hydrazine reduction and electroless plating methods.Their differences in the structures,specific areas and particle sizes were characterized by XRD,BET and TEM,respectively.Furthermore,their catalytic activities for the hydrogen iodide(HI)decomposition were evaluated in a fixed bed reactor.The results show that the catalyst 5%Pt/Al_2O_3 prepared by the electroless plating has the optimum catalytic properties...     

Unsupported palladium alloy foil membranes fabricated by electroless plating

It is desirable to create thin (<25 μm), unsupported, defect-free palladium and palladium alloy foils in a cost-effective manner in order to study intrinsic material properties exclusive of support effects. We have developed a novel technique for producing unsupported palladium films by electroless plating upon mirror-finished stainless steel supports followed by mechanical removal. High quality pure palladium films as thin as 7.2 μm were produced. Single gas steady state permeation experiments were performed using hydrogen and nitrogen to examine permeability and selectivity. The pure palladium membranes showed hydrogen permeabilities comparable to cold-rolled unsupported foils, and high H₂/N₂ selectivity. Palladium-copper membranes were prepared by sequential electroless plating of copper onto palladium foils followed by in situ annealing. The annealing process produces films of desired composition with permeabilities comparable to those in the literature. The annealing process does not appear to produce defects in the film, and the membranes thus produced have performed 15 days without increased leak rates.     

空心微珠表面化学镀Ni-Co-P合金

以无机非金属粉煤灰空心微珠为芯材, 利用化学镀工艺对其表面进行金属化改性, 可以得到表面完整包覆的导电粉体, 该粉体具有中空, 质轻, 粒度细, 高强度, 耐高温, 导电性能好等多种优异性能, 可部分代替金属和铁氧体微粉作为电磁波吸收剂. 采用SnCl2和PdCl2进行敏化-活化处理后, 在空心微珠表面化学包覆Ni-Co-P合金层, 利用XRD、EDS、SEM和镶嵌金相等方法对样品进行形貌观察和分析表征, 结果表明, 使用PdCl2作活化剂可以得到优质均匀的Ni-Co-P合金镀层, 镀层光亮, 均匀, 包覆完整. 化学镀后镀层呈非晶态, 450 ℃氢气气氛下热处理后出现结晶相Ni3P和六方晶系的α-Co单质.     

聚合物基ZnO纳米线的制备和生长机理研究

采用独特的高分子溶液自组装生长方法, 在经化学镀预处理的基底上利用高分子溶液的网络络合效应制备了ZnO纳米线. 通过场发射扫描电子显微镜(FE-SEM), X射线能谱仪(EDS)等对样品的表面形貌及组成进行了观测表征. 结果显示, 纳米线直径约50 nm, 长度达到了数微米; 产物Zn、O化学计量比接近1∶1. 通过Si基底经化学镀工艺预处理和未经化学镀预处理对ZnO纳米结构、紫外吸收和PL性能影响的分析比较, 发现了化学镀Ni对于纳米线长度和直径尺寸的控制更为有效; 在PL图谱中, 经化学镀预处理的样品在中心波长385 nm出现了由激子碰撞复合所形成的近紫外发光峰. 进一步还分析了在不同的pH值和反应时间下样品的紫外吸收和光致发光性能. 通过以上实验, 讨论并提出了ZnO纳米线的生长机理及过程, 认为纳米线的生长是在化学镀催化剂和高分子双重作用下进行的.     

Selective Ni-P electroless plating on photopatterned cationic adsorption films influenced by alkyl chain lengths of polyelectrolyte adsorbates and additive surfactants

We demonstrated that the photopatterned single-layer adsorption film of poly(1-dodecyl-4-pyridinium bromide) on a silica surface was available for a template of nickel-phosphorus (Ni-P) electroless plating through sensitization with a SnCl(2) aqueous solution and activation with a PdCl(2) aqueous solution. Four kinds of poly(1-alkyl-4-vinylpyridinium halide)s bearing methyl, propyl, hexyl, and dodecyl groups were prepared. The cationic polymers were adsorbed by a negatively charged silica surface from their solutions, to form single-layer adsorption films exhibiting desorption-resistance toward deionized water and ethanol. The organic adsorption films could be decomposed completely by exposure to 172 nm deep-UV light. The formation and decomposition of the single-layer films were confirmed by deep-UV absorption spectral measurement and zeta-potential measurement. Ni-P electroless plating was carried out on the photopatterned adsorption films, using three types of SnO(x) colloidal materials without and with cationic or anionic surfactant as catalyst precursors in the sensitization step. In the case of the negatively charged SnO(x) colloids surrounded by anionic surfactant, Ni-deposition took place preferentially on the cationic adsorption films remaining in unexposed regions. The Ni-deposition was accelerated significantly on the cationic adsorption film bearing dodecyl groups. It was obvious by ICP-AES analyses that the hydrophobic long-chain dodecyl groups in the adsorption film could promote the adsorption of the negative SnO(x) colloids on the film surface, followed by much nucleus formation of zerovalent Pd catalysts useful for the electroless plating. The result of our experiment clearly showed that, in addition to electrostatic interaction, van der Waals interaction generating between the hydrophobic long-chain hydrocarbons of the adsorption film and the surfactant improved significantly the adsorption stability of the SnO(x) colloids, resulting in highly selective Ni-deposition in accord with the photopattern shape of the cationic single-layer adsorption film.     

Novel conducting fabric polymer composites as stretchable electrodes: one‐step fabrication of chemical actuators

Composite films have functioned as chemical bending actuators, where stretchable conducting fabrics were joined to both surfaces of ionomer films. This phenomenon shows that a direct metallization of either electroless or electrolytic plating having a metal dendrite formation on the ionomer film is not essential for functioning as actuators. Conducting fabric polymer composite (CFPC) actuators can be easily fabricated by a simple adhesion process using flexible conducting fabrics as electrodes. Due to their excellent contraction and expansion capabilities, gold‐ and copper‐plated knitted fabrics were employed and stably bound to Nafion‐117 film. Au‐CFPC actuators demonstrated a maximum bending displacement of ±2.5 mm at ±2 V. Cu‐CFPC gave a smaller displacement of ±0.7 mm at ±2 V, having no reverse displacement. The method described here is widely applicable, introducing conducting layers on various flexible, stretchable, and polymer substrates. Copyright © 2008 John Wiley & Sons, Ltd.     

Silver particles-modified polysulfonic acid-doped polyaniline layers: electroless deposition of silver in slightly acidic and neutral solutions

Polyaniline layers are produced by electrochemical polymerisation of aniline in the presence of small amounts of poly(2-acryalamido-2-methyl-propane-sulfonic acid) in an inorganic acid solution. Electroactivity and in situ conductance of the obtained polysulfonic acid-doped layers are studied in slightly acidic and neutral solutions. Electroless deposition of silver particles is carried out in silver-EDTA complex ion solutions at pH????.2 and pH????.6 by using the polyaniline layers as reductant. The amount of electroless-deposited silver is studied depending on: polymerisation charge used to synthesize the polymer layer, pH of the plating solution, metal ion concentration and dipping time. SEM shows in all cases a highly non-homogeneous distribution of the metallic phase over the surface, the most protruding fibrillar polymer structures favouring the electroless silver deposition. A linear dependence between amount of the polyaniline material and amount of deposited silver is found for the silver plating solutions with the highest investigated concentration (10?mmol?l^??). At lower concentrations (2.0 and 0.4?mmol?l^??), the same amount of silver becomes deposited on polymer layers with markedly different charges. The electroless deposition of silver in the solutions with lower acidity results in lower amounts of deposited silver at otherwise identical conditions. Effects such as charge transfer within the polymer phase and mass transport in the solution are addressed to explain the observed dependencies of the amount of deposited silver on concentration and pH in the different plating solutions.     

Using electroless deposition for the preparation of micron sized polymer/metal core/shell particles and hollow metal spheres

Uniform and stable core-shell microspheres composed of a poly(methyl methacrylate) (PMMA) core and a thin metallic shell of nickel-phosphorus, cobalt-phosphorus, or mixed metal alloys (CoNiP, NiFeP, CoFeP) were prepared by dispersion polymerization of methyl methacrylate followed by electroless plating. The presence of the metallic shell around the particles was confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and photoelectron spectroscopy. Transmission electron microscopy images of the cross-section of individual particles show that the thickness of the metal/alloy can be precisely tuned by adjusting the immersion time of the microspheres in the electroless bath. Depending on the deposited metallic material, various magnetic properties, from paramagnetic to ferromagnetic, are achieved. Finally, uniform hollow metallic spheres composed of nickel, cobalt, or nickel-cobalt alloy are obtained by dissolving the polymer core.     

Preparation of ordered and crosslinked films from liquid crystalline vinyl ether monomers

Thermally stable ordered films were prepared by in-situ photopolymerization of an oriented monomer mixture, consisting of mesogenic monofunctional and bifunctional vinyl ethers. Orientation was achieved by a simple surface treatment, using an unidirectionally rubbed polyimide film. The films restored their orientation when cooled down from temperatures of 200°C. Highly ordered densely crosslinked films have been prepared by polymerization of bifunctional mesogenic vinyl ether monomers. Polymerization from various monomer phases resulted in LC polymer network films with different molecular organizations. It was shown that films with nematic, smectic A and smectic B structures were obtained, the latter having a very high degree of orientation. The films were analyzed with small-angle X-ray scattering, polarized light microscopy and infrared- dichroism measurements.     

Silver particles-modified polysulfonic acid-doped polyaniline layers: electroless deposition of silver in slightly acidic and neutral solutions

Polyaniline layers are produced by electrochemical polymerisation of aniline in the presence of small amounts of poly(2-acryalamido-2-methyl-propane-sulfonic acid) in an inorganic acid solution. Electroactivity and in situ conductance of the obtained polysulfonic acid-doped layers are studied in slightly acidic and neutral solutions. Electroless deposition of silver particles is carried out in silver-EDTA complex ion solutions at pH = 4.2 and pH = 6.6 by using the polyaniline layers as reductant. The amount of electroless-deposited silver is studied depending on: polymerisation charge used to synthesize the polymer layer, pH of the plating solution, metal ion concentration and dipping time. SEM shows in all cases a highly non-homogeneous distribution of the metallic phase over the surface, the most protruding fibrillar polymer structures favouring the electroless silver deposition. A linear dependence between amount of the polyaniline material and amount of deposited silver is found for the silver plating solutions with the highest investigated concentration (10 mmol l⁻¹). At lower concentrations (2.0 and 0.4 mmol l⁻¹), the same amount of silver becomes deposited on polymer layers with markedly different charges. The electroless deposition of silver in the solutions with lower acidity results in lower amounts of deposited silver at otherwise identical conditions. Effects such as charge transfer within the polymer phase and mass transport in the solution are addressed to explain the observed dependencies of the amount of deposited silver on concentration and pH in the different plating solutions.

     

Repair of Pd/α-Al_2O_3 composite membrane with defects

A palladium composite membrane with a large number of defects was repaired using the electroless plating combined with the technique of osmosis. The loose structure of palladium film prepared by the conventional electroless plating was densified. Defects were repaired. Hydrogen selectivity was thus significantly increased without significantly increasing palladium film thickness and reducing hydrogen permeability.     

Template‐Synthesized Copper Nanotubes via Electroless Plating

Template synthesis method of preparing copper nanotubes via electroless plating has been investigated in this paper. The tubular structures were obtained by calcinring copper‐coated carbon nanofibers. The final products were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), and x‐ray diffractometer (XRD). The results show that copper nanotubes can be synthesized by this method. The inner diameter of the prepared copper nanotubes is about 100 nm, and the wall thickness is about 25 nm. In this method, it is convenient to control the dimension or the shape of the obtained copper nanotubes by using different nanofibers as templates.     

不同化学镀液中p－Si上激光诱导局部沉积铜

在化学镀铜浴液中,p-Si片在彼长为514.5nm的激光束的照射下,得到了选择性的铜镀层。采用AEs、SEM、RBS和电学技术对比了在3种含不同还原剂的镀液中得到的镀层的形貌、组成、界面扩散及电学性质;探讨了液相激光诱导化学沉积铜的机理。