RF—PECVD聚合类聚乙烯氧（PEO—like）薄膜及其对血小板吸附性研究

本文采用平板式电容耦合射频(RF,13.56MHz)等离子体源,以乙二醇二甲基醚(Ethylene Glycol DiMethyl Ether)为聚合单体,氩气为辅助气体,在连续与脉冲射频等离子体两种放电模式下合成类聚乙烯氧(PEO-like)功能聚合薄膜.实验研究了等离子体放电参数:等离子体放电功率、工作气压、放电模式(连续或脉冲)和聚合时间等对聚合物表面结构、功能团含量、表面成分性能以及和血小板吸附等影响.利用接触角测定仪(WCA)、傅里叶变换红外光谱(FTIR)、原子力显微镜(AFM)等手段对聚合薄膜的结构、成分和形貌进行细致的分析.同时本文还进行体外细胞培养法,研究了类PEO功能薄膜对富血血小板的吸附,通过倒置显微镜观察细胞黏附的数量和形态变化.得到的结论为:采用RF-PECVD可以在较小功率的连续等离子体放电模式,或较长脉冲间隔的脉冲放电模式下得到结构稳定的PEO生物功能薄膜,所制备的PEO生物功能薄膜具有良好的抗血小板吸附性能.     

Moletronics: future electronics

Over the past several years there have been dramatic advances toward the realization of electronic computers integrated on the molecular scale. First, individual molecules were demonstrated that serve as incomprehensibly tiny switches and wires one million times smaller than those on conventional silicon microchips1, 2, 3, 4. This has resulted very recently in the assembly and demonstration of tiny computer logic circuits built from such molecular-scale devices4, 5, 6, 7, 8, 9, 10.A major force responsible for these revolutionary developments has been the molecular electronics or ‘Moletronics’ Program organized by the US Government's Defense Advanced Research Projects Agency (DARPA). Previously, DARPA gave birth to the Internet in the 1970s and 1980s, revolutionizing the way the world communicates. Now, the agency is setting its sights on a new revolution in the nature, structure, and scale of the very materials with which the world both computes and builds. Ultimately, to compute with molecular-scale structures — i.e. nanometer-scale structures — one must learn how to characterize and organize them on similar scales, one by one and in vast arrays. This is creating a whole new science and industry of ‘nanostructured materials’, such as are portrayed in Fig. 1

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Fig. 1. Moletronics nanostructured materials. (a) Electron micrograph of self-assembled ErSi₂ nanowires developed at HP. (Reproduced with permission from⁵⁴.); (b) electron micrograph of cowpea viral particle modified with gold nanoclusters developed at NRL to use as a template for molecular self-assembly; (c) simulation of Rice University's gold-nanoparticle electrical contacts on a surface in a ‘NanoCell’ molecular logic structure⁵¹; (d) structural diagram of NDR diode switch molecule20, 28, 35 and a simulation of its molecular orbitals involved in switching. (Reproduced with permision from⁴⁷. Copyright 2000 American Chemical Society.); (e) gold nanobars synthesized at PSU; (f) electron micrograph of nanowire transistor-based logic circuit⁴ that was self-assembled and demonstrated at Harvard University.(Reprinted with permission from⁵. Copyright 2001 American Association for the Advancement of Science.)

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Cold electronics: an overview

Low-temperature operation is being applied and contemplated for electronic systems ranging from single-transistor circuits for basic research to VLSI integrated circuits for ultra-fast computers. It is seen as both a means of extracting better performance from present technology and as an important ingredient of the next generation of devices and circuits. This overview is concerned with electronics based on semiconductors; for low temperatures the primary material is Si, although GaAs also has considerable potential, and the primary device is the field-effect transistor in various forms. Reduced temperature operation offers improvements in performance through improvement of materials-related properties such as electronic carrier mobility, thermal conductivity, and electrical conductivity. Substantial improvements in reliability are also expected since degradation mechanisms are thermally activated; however, this could be negated unless problems of thermal expansion mismatch and cycling are overcome. Refrigeration continues to be a central concern; mechanical cycles are still the mainstay and progress is being made in systems applicable to electronics, although further development is needed.