Layer-by-layer self-assembly of polyethyleneimine and poly(4-styrene sulfonic acid-co-maleic acid) forming composite polyelectrolyte membranes for pervaporation of aqueous alcohol solutions

Abstract

Composite polyelectrolyte pervaporation membranes were fabricated through layer-by-layer self-assembly method. Cationic polyethyleneimine (PEI) and anionic poly(4-styrene sulfonic acid-co-maleic acid) (PSSMA) polyelectrolytes were deposited one after the other on a porous asymmetric modified polyacrylonitrile (mPAN) substrate. Attenuated total reflection–Fourier transform infrared spectral analysis and X-ray photoelectron spectrometry confirmed the deposition of polyelectrolytes on the mPAN support. Field emission scanning electron microscopy depicted that pores in the mPAN support were covered with layers of polyelectrolytes. Atomic force microscopy illustrated that the deposition of polyelectrolytes led to a smooth surface of the membrane. Moreover, the membrane exhibited improved hydrophilicity. We investigated the effect of polyelectrolyte concentrations on the efficiency of dehydrating 90 wt% aqueous alcohol solutions through pervaporation. The results established that bilayer polyelectrolyte membranes fabricated from 0.9 wt% PEI and 0.1 w% PSSMA delivered maximal dehydration efficiency.