微模塑技术在聚乙烯上刻制备条纹

以聚二甲基硅氧烷为弹性印章,低密度聚乙烯为材料,在平面、一般曲面乃至毛细管的微突起上微模塑出了清晰的微条纹。     

微模塑法制备PMMA球面微透镜阵列

Micro-lens (ML) and Micro-lens array (MLA) are important optical components widely used in many fields;Soft-lithography, a vital little process technology, has its unique performance to produce ML and MLA;The cylinder and spherical MLA of polymethyl methacrylate (PMMA) were successfully obtained by micromolding inSoft-lithography. Some suitable experimental parameters in the process were discussed, and the imaging property of the MLA was also studied simply.     

微模塑技术在聚乙烯上刻制微条纹

以聚二甲基硅氧烷为弹性印章,低密度聚乙烯为材料,在平面、一般曲面乃至毛细管的微突起上微模塑出了清晰的微条纹.     

微热模塑法制备聚苯乙烯球面微透镜阵列

用软刻蚀中的微热模塑技术制备聚苯乙烯(PS)微立方体阵列, 再利用材料在液态或熔融状态时其表面自由能会不断地减小直至最低从而达到最稳定的状态这一特性, 通过加热熔融方法成功地将PS微立方体结构变成了PS微半球体结构, 光学成像测试验证了PS微半球体阵列具有良好的光学成像功能, 可以作为微透镜阵列使用. 用微热模塑技术制备高聚物的微透镜阵列, 其过程简单, 成本低, 适用于很多材料, 所制备的微透镜阵列结构精确度高, 并因所用到的模具为弹性印章, 有望在非平面上制备微透镜阵列, 为微透镜阵列的制备提供了一种新的途径.     

拉伸微模塑制备低密度聚乙烯超疏水表面

以新鲜荷叶为原始模板制备聚二甲基硅氧烷(PDMS)软模板,并用该软模板在真空下热压得低密度聚乙烯(LDPE),冷却剥离得到LDPE超疏水薄膜.场发射扫描电镜(FE-SEM)显示其表面由细长乳突(长约30 μm)构成,接触角为154°±3.5°,水滴极易滚落,而常压下热压得到的薄膜表面乳突则短而粗(长约8～10μm),接触角仅137°±2.7°,短粗的乳突高度接近模板微坑的深度,证明细长乳突是在微模塑脱模时拉伸形成的.     

聚合物三维微图案加工的转移微模塑新方法

光刻蚀技术是微电子加工技术中最成功的一种,但由于受到光学衍射等的限制,100nm是光刻蚀的极限,为此人们探索了许多先进的刻蚀技术,如超紫外线刻蚀(EUV)、软X射线刻蚀、电子束刻蚀和聚焦离子束刻蚀(FIB)等,可制作尺寸小于100nm的图形,但普遍存在加工速度慢及成本高等缺点.     

用毛细微模塑法制造无机盐及聚合物的微结构

软刻蚀;弹性印章;聚二甲基硅氧烷;用毛细微模塑法制造无机盐及聚合物的微结构     

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.     

壳聚糖微图形的制备及表征

通过微转移模塑法, 在硅片表面制备了圆形点阵、 方形点阵、 沟槽和波浪等4种形貌的壳聚糖(CS)微图形. CS微图形清晰规整, 成型效果良好. 成骨细胞在圆形点阵和方形点阵上借助伪足多攀附于点阵凸起处. 点阵图形对细胞增殖和分化无影响. 在沟槽和波浪微图形中, 成骨细胞大多被限制在沟区, 且沿着沟槽方向伸展. 沟槽和波浪微图形不利于细胞分化, 但能促进细胞增殖.     

Evaluation of high-performance liquid chromatography column retentivity using macromolecular probes I

The application of macromolecular probes is proposed for evaluation of HPLC column retentivity. The idea is tested with a set of different commercial silica C₁₈ reversed-phases. For comparison, porous glass C₁₈ and polystyrene/divinylbenzene column packings are also included. Polar, mainly silanophilic interactions are evaluated. The retention volumes of a series of narrow molar mass distribution polystyrenes (PS) and poly(methyl methacrylate)s (PMMA) in toluene eluent are compared. Toluene is a weak mobile phase concerning silica gel surface and it promotes adsorption of PMMA on silanols, while PS is not adsorbed from toluene. Simultaneously, toluene is a thermodynamically good solvent for both polymers so that extensive partition in favour of stationary phase is not probable. Differences in retention behaviour of PS and PMMA indicate presence of abundant free silanols on the surface of some reversed-phases. These silanols are accessible even for large macromolecules of PMMA. Pore diameter and pore volume of the column packing can be semiquantitatively evaluated from the elution data of PS in toluene in the course of retentivity tests.     

Purification and partial characterization by matrix-assisted laser desorption ionization time-of-flight mass spectrometry of the recombinant transposase,TniA

This work deals with zone electrophoresis (ZE) separations of proteins on a poly(methyl methacrylate) chip with integrated conductivity detection. Experiments were performed in the cationic mode of the separation (pH 2.9) with a hydrodynamically closed separation compartment and suppressed electroosmotic flow. The test proteins reached the detector in less than 10 min under these working conditions and their migration times characterized excellent repeatabilities (0.1–0.6% RSD values). The chip-to-chip agreements of the migration times, evaluated from the ZE runs performed on three chips, were within 1.5%. The conductivity detection provided for protein, loaded on the chip at 10–1000 μg/ml concentrations, detection responses were characterized by 1–5% RSD values of their peak areas. Such migration and detection performances made a frame for reproducible baseline separations of a five-constituent mixture (cytochrome c, avidin, conalbumin, human hemoglobin and trypsin inhibitor). On the other hand, a high sample injection channel/separation compartment volume ratio of the chip (500 nl/8500 nl) restricted the resolution of proteins of very close effective mobilities in spite of the fact that in the initial phase of the separation an electric field stacking was applied. A maximum macroconstituent/trace constituent ratio attainable for proteins on the chip was assessed for cytochrome c (quantifiable when its concentration in the loaded sample was 10 μg/ml) and apo-transferrin (containing a trace constituent migrating in the position of cytochrome c detectable when the load of apo-transferrin was 2000 μg/ml). This assessment indicated that a ratio of 1000:1 is attainable with the aid of conductivity detection on the present chip.     

Analysis of amino acids and proteins using a poly(methyl methacrylate) microfluidic system

Plastic microchips are very promising analytical devices for the high-speed analysis of biological compounds. However, due to its hydrophobicity, their surface strongly interacts with nonpolar analytes or species containing hydrophobic domains, resulting in a significant uncontrolled adsorption on the channel walls. This paper describes the migration of fluorescence-labeled amino acids and proteins using the poly(methyl methacrylate) microchip. A cationic starch derivative significantly decreases the adsorption of analytes on the channel walls. The migration time of the analytes was related to their molecular weight and net charge or pI of the analytes. FITC-BSA migrated within 2 min, and the theoretical plate number of the peak reached 480,000 plates/m. Furthermore, proteins with a wide range of pI values and molecular weights migrated within 1 min using the microchip.     

Absorption and photoluminescence of Buriti oil/polystyrene and Buriti oil/poly(methyl methacrylate) blends

This work reports the preparation and characterization of Buriti (Mauritia flexuosa L.) oil/polystyrene (PS) and Buriti oil/poly(methyl methacrylate) blends. The Buriti is an abundant palm tree of the Amazon region. This oil was used because of its chemical composition (high concentrations of oleic acid, tocopherols and carotenoids, especially β-carotene) and interesting optical properties, such as absorption and photoluminescence. The incorporation of the vegetable oil in the PS and PMMA matrices renders orange-colored blends, which were verified to absorb UV-Vis radiation and emit light in the green region. The intensity of these properties is proportional to the oil content in the samples. Micrographs of the blends showed that the oil is located in cavities distributed in the polymeric matrices. This work shows that it is possible to employ the Buriti oil, a cheaper and abundant natural resource, to improve absorption and light emission properties of PS and PMMA polymers.     

原位聚合制备的离子液体/聚合物电解质的研究

采用原位聚合制备出新型的BMIPF6/PMMA聚合物电解质透明弹性膜. 研究结果表明, BMIPF6/PMMA聚合物电解质体系在305 ℃时仍具有较好的热稳定性, 其安全性能优于含有机溶剂的传统非水电解质体系. 随着离子液体含量的增加, 其玻璃化转变温度逐渐减小, 离子电导率升高; 且离子电导率与温度的关系服从VTF方程. 其中, 当BMIPF6的质量分数为50%时, 该聚合物电解质的室温离子电导率高达0.15 mS/cm.     

Surface modification of poly(methyl methacrylate) microfluidic devices for high-resolution separations of single-stranded DNA

While polymer-based microfluidic devices offer some unique opportunities in developing low-cost systems for a variety of application areas, the ability to sort electrophoretically with high efficiency a number of different targets has remained somewhat elusive with an example consisting of achieving single base resolution as required for DNA sequencing. While the reasons for this are many-fold, it is clear that some type of coating is required on the polymer substrate to suppress the EOF and/or minimize potential solute/wall interactions. To this end, we report on a simple grafting procedure to allow the formation of polymer coats, which in this example used linear polyarcylamides (LPAs), onto a poly(methyl methacrylate) (PMMA) microfluidic device. The procedure involved creating an amine-terminated PMMA surface by appropriately functionalizing the PMMA through either a chemical or photochemical process. The aminated surface could then be used to covalently anchor methacrylic acid, which was used as a scaffold to produce LPAs on the surface through radical polymerization of acrylamide. The resulting surfaces demonstrated EOFs that were nearly an order of magnitude smaller than native PMMA. In addition, these LPA-coated devices could produce highly reproducible migration times of over approximately 20 runs with plate numbers exceeding 10(5) m(-1). Using gel electrophoretic analysis of a single base track generated from an M13mp18 template using Sanger cycle sequencing and dye-primer chemistry, the resolution value obtained for bases 199 and 200 was 0.18 while for bases 208 and 209 it was 0.21. For the native PMMA, these bands were found to comigrate.     

凝聚条件对聚甲基丙烯酸甲酯薄膜银纹化现象的影响

<正> 当玻璃态聚合物受张力作用时,常可以观察到银纹形成,它是聚合物材料内部断裂的先兆,银纹是垂直于拉伸方向的平面缺陷,与正常裂纹不同,银纹的质量不是零,而是由沿拉伸方向排列的高度应变的微纤及孔穴组成,银纹的典型尺寸约为长100μm,宽1—2μm,微纤的直径约5—15nm,微纤的总体积分数约占20—50％,微纤能支撑负荷,因此银纹在控制聚合物屈服以后的力学行为中的作用一直是个重要的研究领域。近年来从聚合物分子缠结网对银纹生长,微纤断裂及银纹稳定性的影响方面做了一些有意义的工作。     

Impact of fullerenes on the thermal stability of melt processed polystyrene and poly(methyl methacrylate) composites

The impact of the two fullerenes C₆₀ and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) on the thermal and thermo-oxidative stability of the corresponding melt processed composites with the two polymers polystyrene (PS) and poly(methyl methacrylate) (PMMA), was studied using both dynamic and isothermal thermogravimetric analysis (TGA). For each polymer, three different composites with C₆₀ loadings of 1.0 wt% and 3.0 wt% and PCBM loadings of 1.0 wt% were considered. The aim of this work was to compare the stabilization effect of both fullerenes on PS and PMMA. The results obtained show unequivocally that, although PCBM has lower thermal and thermo-oxidative stability than C₆₀, the PS-PCBM and PMMA-PCBM composites have higher thermal and thermo-oxidative stability than the corresponding PS-C₆₀ and PMMA-C₆₀ composites. These results corroborate our previous reports, on showing that PCBM is better than C₆₀ at improving the thermal and thermo-oxidative stability of polymers which degrade through radical degradation mechanisms.     

聚合物表面自组装电极的制备

采用在聚合物表面制备选择性化学镀电极的方法, 将具有电极结构的模板置于聚萘二甲酸乙二醇酯(PEN)基片表面上, 用紫外光进行照射, 使辐照区域表面形成羧基, 然后通过配位作用使银离子附着到表面上, 再经过紫外光照射还原出金属银颗粒, 最后以表面的金属银颗粒为催化剂进行特定区域化学镀铜形成电极. 利用四探针法测得电极的电阻率为5.063×10-2 Ω·mm2/m, 与纯金属铜的电阻率的数量级相同.