Polynorbornene copolymers combining flexible ether side chains and rigid hydrophobic segments for AEMWE†

In this study, we report the synthesis of copolymers incorporating an ether-sidechain containing (EM) and a sterically hindered hydrophobic, anthracene-derived norbornene monomer (AM). Using this copolymer system, we developed both block and statistical copolymers, with the latter demonstrating excellent potential for the fabrication of robust anion exchange membranes (AEMs) when blended with poly(oxindolebiphenylene) (POB). Stable membranes with controllable swelling and water uptake properties were obtained. The composition of the blend was systematically varied to evaluate the effects of different POB ratios on membrane conductivity, stability, and performance in anion exchange membrane water electrolysis (AEMWE). The blend membrane comprising 10 wt% POB and 90 wt% of the statistical copolymer EM_0.54-q-co-AM_0.46-h demonstrated excellent AEMWE performance, delivering a current density of 2.0 A cm⁻² at 1.91 V without the use of platinum group metal (PGM) catalysts, and under a dry cathode configuration.