PARAMETERS INFLUENCING TRANSPORT ACROSS CONDUCTING ELECTROACTIVE POLYMER MEMBRANES

The parameters which influence electrochemically facilitated transport of electroinactive ions across conducting electroactive polymer membr anes have been investigated. The design of membranes and the materials used as well as transport cells and systems have been addressed to im prove selectivity and flux. Polypyrrole-para-toluenesulfonate (PPy-pTS ) was compared with the copolymer of pyrrole with 3-carboxy-4-methylpy rrole (PPy/PCMP-pTS) and their different chemistries resulted in diffe rent membrane selectivities for ions. Platinum mesh was found to be th e most suitable auxiliary electrode material and its placement in the cell chamber(s) facilitated ion incorporation/expulsion at the membran e working electrode. This enhanced the flux of ion transport. The flux can also be further enhanced by narrowing the distance between the me mbrane working electrode and the platinum mesh auxiliary electrode(s), and/or by stirring to improve the hydrodynamics. An alternative cell design, namely a dual membrane flow through cell, also proved to be mo re efficient for ion transport. Good connection geometry to the membra ne as well as the application of a square wave pulsed potential wavefo rm to the membrane was found to be essential for achieving high and su stainable flux in ion transport.