Advances in the design of self-supported ion-conducting membranes – New family of columnar liquid crystalline polyamines. Part 2: Ion transport characterisation and comparison to hybrid membranes

Abstract

Abstract An evaluation of ion transport in new biomimetic membranes, which are based on dendronised liquid crystalline polyamines is described. Two-step modification of starting polymer allowed preparation of self-supported membranes. Current-Voltage curves confirmed cation permselective nature of these new membranes and size-dependent preferential selectivity in following order: H+ > Na+ > Ag+ > K+. However, in case of chloride solutions, damage of the membranes was observed and was studied using SEM, TEM and 1H NMR techniques. Selectivity of self-supported systems was compared with hybrid systems based on similar liquid crystalline polyamines and showed lower selectivity values in case of new membranes. Taking into account improved mechanical stability, extended liquid crystalline behaviour and higher clearing temperature values, these materials seem to address all disadvantages of hybrid systems, therefore are complementary in terms of practical application requiring selective ion transport.