Flexible Conductive Polymer Membranes

与大多数人造塑料的绝缘体不同，导电聚合物可以导电，因为它们具有称为共轭的特殊化学结构。掺杂后，即添加带电分子，共轭聚合物链中原本定位的电荷被动员起来，通过材料携带电。例子包括聚吡咯、聚噻吩和聚苯胺。然而，也正是由于这种共轭分子结构，导电聚合物大多是刚性、脆性和非柔性的。缺乏机械灵活性极大地限制了它们在膜和储能技术等领域的应用。为了克服这一缺点，导电聚合物通常与其他柔性聚合物组成以获得机械性能，例如涂覆在纺织品或柔性聚合物膜表面。这种涂层必须非常薄，否则会损害基材的机械性能。涂层也很容易分层，经常从基材上脱落。在文献中，还没有关于未经改性的本征导电聚合物制成厚柔性膜的报道。***PI的团队最近发现了一种简单的合成工艺，可以制备大尺寸厚（高达1毫米）的纳米多孔聚吡咯膜，在室温和-196℃的液氮温度下都具有优异的膜柔韧性。这种聚吡咯膜具有非常高的表面积，良好的导电性，并且非常轻。从科学上讲，这是首次发现柔性聚吡咯。该膜具有高表面积、高电导率、高离子活性、轻、低温性能等优点，在储能、电池、防静电、场屏蔽等广泛领域具有巨大的应用潜力。然而，我们仍然不知道这种结构是如何形成的机制，以及为什么它在-195℃下仍具有如此的灵活性。******本提案旨在实现以下目标：研究这种膜是如何形成的；2. 研究膜的结构-性能关系。3. 探讨用其他类型的导电聚合物生产类似膜的可能性。4. 确定这些膜的潜在应用，包括在合成过程中或合成后膜的功能化。******该项目将培养2名高素质人才，其中1名具有高分子化学和高分子工程背景，从事合成和膜分析工作。另一位具有材料力学背景，研究力学性能与纳米结构的关系。

Unlike most manmade plastics that are insulator to electricity, conductive polymers can conduct electricity owning to their specific chemical structure called conjugation. Upon doping, i.e., addition of charged molecules, the originally localized charges in conjugated polymer chains become mobilized to carry electricity through the material. Examples include polypyrrole, polythiophene and polyaniline. However, it is also because of this conjugated molecular structure conductive polymers are mostly rigid, brittle and non-flexible. The lack of mechanical flexibility has greatly limited their applications in areas such as membrane and energy storage technologies. To overcome this drawback conductive polymers are often composed with other flexible polymers to gain mechanical performance, for example, coated on textiles or on flexible polymer membrane surface. Such coating has to be very thin otherwise it will compromise the mechanical property of the substrate. The coating also easily delaminates and often detaches from the substrate. In literature there has been no report on thick flexible membranes made of unmodified intrinsically conductive polymers. ***PI's group recently discovered a simple synthetic process to prepare large sized thick (up to 1 mm) nanoporous polypyrrole membranes with excellent membrane flexibility at room temperature and all way down to liquid nitrogen temperature that is -196 oC. This polypyrrole membrane has very high surface area, good electrical conductivity, and is extremely light. Scientifically this is the first discovery of flexible polypyrrole. Such membrane may have great potential in wide spectrum of applications such as energy storage, battery, antieletrostatic and field shielding, owing to its high surface area, electrical conductivity and ionic activity, lightness and low temperature performance. However, we still don't know the mechanism about how such structure is formed and why it has such flexibility even at -195 oC. ******This proposal is aiming at following objectives: 1. To investigate how such membrane is formed; 2. To study the structure-property relationship of the membrane. 3. To investigate the possibility of producing similar membrane with other types of conductive polymers. 4. To identify the potential application of such membranes, including the functionalization of the membranes during or after synthesis.******This project will train 2 highly qualified personnel, one with background in polymer chemistry and polymer engineering, to work on synthesis and membrane analysis. Another with background in material mechanics, to study the how the mechanical properties are related with nanostructures.