用微模塑直接在聚合物曲面上制备微图形

用聚二甲基硅氧烷制备的 ,表面复制有微图形的“弹性印章”直接在聚乙烯 ,聚丙烯 ,聚苯乙烯和聚甲基丙烯酸甲酯等热塑性聚合物表面上进行热微模塑 ,无需复杂设备并可在普通实验室条件下 ,复制微图形 ,甚至在小试管外壁的曲面上或在用毛细管形成的微突起表面上也能制备出微曲面图形 .讨论了不同聚合物对生成微图形的影响 ,认为结晶性聚合物以及在温度变化时有较大收缩率的聚合物在微模塑中难以获得清晰图形 .无定形聚合物如聚苯乙烯和聚甲基丙烯酸甲酯等能够获得清晰的微结构     

TiO2微图纹结构的制作

用软刻蚀技术中具有代表性的方法———微模塑法和转移微模塑法 ,在普通光学玻璃表面成功制备出TiO2 微阵列结构 .首先 ,以钛酸四丁酯为前驱物 ,通过溶胶 凝胶法合成出TiO2 溶胶 ,然后用表面带有微图纹的有机硅橡胶PDMS作为弹性印章分别对所制得的TiO2 溶胶进行微模塑及转移微模塑加工 ,在 70℃下溶胶凝胶 ,进而让凝胶材料在 5 5 0℃下焙烧 2h得到TiO2 微结构 .用光学显微镜对所得到的微结构进行了显微观察 ,显微照片显示 ,微模塑法和转移微模塑法在制备材料微结构方面复制精细度和重复率都比较令人满意 .同时 ,还初步探讨了影响最终图纹复制效果的凝胶温度、外加压力及模板等因素     

微模塑法制备PMMA/SiO2二氧化硅杂化材料微结构

PMMA/ SiO2 organic-inorganic hybrid sol was synthesized by monomer methyl methacrylate,3-（triethoxysilyl）propylmethacrylate（mol ration is 1: 1）,0.2%（total weight of monomers）initiator azodiisobutyronitrile,solvent tetrahydrofuran and 20%（total weight of the system）tetraethylorthosilicate. PDMS stamp with micropatterns was placed on the hybrid sol film prepared by spin-coating on the clean glass slides. Heat treatment under 120℃ for 2 h with a weak pressure of 1 N makes the sol convert to gel. PMMA/SiO2 hybrid material micropatterns remain on the substrate after being peeled off the stamp. Optical microscope images show stringent pattern fidelity using the micromolding method which also indicates the further application in the micropatterns fabrication.     

毛细微模塑法制作聚合物微球的有序结构

用毛细微模塑法在玻璃基片上组装了聚苯乙烯微球紧密的有序阵列 .扫描电镜观察了组装后的微球排列 .结果表明 ,在毛细通道的出口端 ,聚苯乙烯的微球堆积得紧密有序 .毛细通道的尺寸 ,环境温度和聚合物微球乳液的浓度是毛细微模塑法的主要影响因素 .     

溶胀后的弹性印章进行毛细微模塑

Micromolding in capillaries of a micro-square array was carried out for polystyrene solution in acetone by means of swollen polydimethylsiloxane (PDMS) elastomeric stamp. The resulting micro-cubic poles were isolated and separable when the added amount of the polystyrene solution was small. Some special distorting micro-patterns in the micro-square array were observed because of shrinkage resulting from the varying evaporation rate of solvent at different places.     

Surface characterization using chemical force microscopy and the flow performance of modified polydimethylsiloxane for microfluidic device applications

The widespread interest in micro total analysis systems has resulted in efforts to develop devices in cheaper polymer materials such as polydimethylsiloxane (PDMS) as an alternative to expensive glass and silicon devices. We describe the oxidation of the PDMS surface to form ionizable groups using a discharge from a Tesla coil and subsequent chemical modification to augment electroosmotic flow (EOF) within the microfluidic devices. The flow performance of oxidized, amine-modified and unmodified PDMS materials has been determined and directly compared to conventional glass devices. Exact PDMS replicas of glass substrates were prepared using a novel two step micromolding protocol. Chemical force microscopy has been utilized to monitor and measure the efficacy of surface modification yielding information about the acid/base properties of the modified and unmodified surfaces. Results with different substrate materials correlates well with expected flow modifications as a result of surface modification. Oxidized PDMS devices were found to support faster EOF (twice that of native PDMS) similar to glass while those derivatized with 3-aminopropyl triethoxysilane (APTES) showed slower flow rates compared to native PDMS substrates as a result of masking surface charge. Results demonstrate that the surface of PDMS microdevices can be manipulated to control EOF characteristics using a facile surface derivatization methodology allowing surfaces to be tailored for specific microfluidic applications and characterized with chemical force microscopy.     

毛细微模塑法制作聚合物微球的有序结构

用毛细微模塑法在玻璃基片上组装了聚苯乙烯微球紧密的有序阵列.扫描电镜观察了组装后的微球排列.结果表明,在毛细通道的出口端,聚苯乙烯的微球堆积得紧密有序.毛细通道的尺寸,环境温度和聚合物微球乳液的浓度是毛细微模塑法的主要影响因素.