Switchable gas permeability of a polypropylene‐liquid crystalline composite film

The development of functionalized polyolefins for use as stimuli-responsive commodity polymers has recently received much attention. In this work, a microporous polypropylene (PP) scaffold is used to align and fortify smectic liquid crystalline network (LCN) which can switch its gas permeability upon pH changes. LCN photopolymerized mixture dimerized benzoic acid derivative monoacrylate diacrylate crosslinker. the hydrogen-bonded state, composite membrane shows high-molecular order low He, N2, CO2 gases. By switching from state salt form, molecular reduced, increased by one magnitude. This increase mainly attributed loss in system, increasing free volume, resulting an diffusibility. exposing film basic or acidic environments, reversible between high states observed, respectively. physical constraints imposed PP strengthens while inside polymer maintained. permeation properties not possible with fragile freestanding films alone.