Nanofiber Composite Ion-Exchange and Bipolar Membranes

这项由美国国家科学基金会颁发的化学和生物分离项目奖支持范德比尔特大学的Peter Pintauro教授为阴离子交换、阳离子交换和双极膜开发新的制造策略和新的纳米形态。膜将通过静电纺丝同时制备功能离聚体（离子交换聚合物）和不带电（惰性）增强聚合物的纳米纤维。由此产生的双纤维垫将被加工成具有两种相分离形态之一的膜：(i)被不带电的聚合物基体包围的离聚体纳米纤维或（ii）被带电的离聚体包围的不带电的聚合物纳米纤维。在这两种纳米纤维复合膜设计中，带电聚合物（为离子和溶剂输送提供途径）的功能与惰性/不带电聚合物材料（为膜提供机械强度和限制离聚体膨胀）的功能是分离的。因此，嵌入式纳米纤维网络的使用代表了膜制造方式和膜纳米形态控制/操纵方式的范式转变。实验工作将主要集中在阴离子交换和双极膜。所得薄膜将具有更好的机械性能，更高的离子通量和电导率，以及更好的分离选择性。这种膜的应用包括电析盐分离、工业电化学过程、双极膜水分解和化学传感器。

This NSF award by the Chemical and Biological Separations program supports work by Professor Peter Pintauro at Vanderbilt University to develop new fabrication strategies and new nano-morphologies for anion-exchange, cation-exchange, and bipolar membranes. Membranes will be prepared by electrospinning simultaneously nanofibers of a functional ionomer (ion-exchange polymer) and an uncharged (inert) reinforcement polymer. The resulting dual fiber mat will be processed into a membrane with one of two phase-separated morphologies: (i) ionomer nanofibers surrounded by an uncharged polymer matrix or (ii) uncharged polymer nanofibers surrounded by charged ionomer. In these two nanofiber composite membrane designs, the function of the charged polymer (providing pathways for ion and solvent transport) is decoupled from that of the inert/uncharged polymeric material (providing mechanical strength to the membrane and restricting ionomer swelling). Thus, the use of embedded nanofiber networks represents a paradigm shift in the way membranes are made and the way membrane nano-morphology is controlled/manipulated. Experimental work will focus primarily on anion-exchange and bipolar membranes. The resulting films will have improved mechanical properties, higher ion fluxes and conductivity, and better separation selectivity. Applications for such membranes include electrodialytic salt separations, industrial electrochemical processes, bipolar membrane water splitting, and chemical sensors.