Porous membranes built up from hydrophilic poly(ionic liquid)s

TL;DR

This paper introduces a novel method for fabricating porous membranes from water-soluble poly(ionic liquid)s using electrostatic complexation and phase separation, resulting in stimuli-responsive porosity suitable for filtration applications.

Contribution

First demonstration of porous membranes from hydrophilic poly(ionic liquid)s via electrostatic complexation triggered by neutralization.

Findings

Membranes exhibit stimuli-responsive porosity in different solvents.

Water passes significantly slower through membranes than isopropanol.

Porous structure results from phase separation and ionic complexation.

Abstract

Porous polymer membranes via electrostatic complexation triggered by neutralization are fabricated for the first time from a water-soluble poly(ionic liquid) (PIL). The porous structure is formed as a consequence of simultaneous phase separation of the PIL and ionic complexation, which occurred in a basic solution of a non-solvent for the PIL. These membranes have a stimuli-responsive porosity, with open and closed pores in isopropanol and in water, respectively. This property is quantitatively demonstrated in filtration experiments, where water is passing much slower through the membranes than isopropanol.