Proton‐Conducting Poly(phenylene oxide)–Poly(vinyl benzyl phosphonic acid) Block Copolymers via Atom Transfer Radical Polymerization

Block copolymers containing poly(phenylene oxide) (PPO) and poly(vinyl benzyl phosphonic acid) segments are synthesized via atom transfer radical polymerization (ATRP). Monofunctional PPO blocks are converted into ATRP active macroinitiators, which are then used to polymerize a diethyl p‐vinylbenzyl phosphonate monomer in order to obtain phosphonated block copolymers bearing pendent phosphonic ester groups. Poly(phenylene oxide‐b‐vinyl benzyl phosphonic ester) block copolymers are hydrolyzed to corresponding acid derivatives to investigate their proton conductivity. The effect of the relative humidity (RH) is investigated. The proton conductivity at 50% RH and one bar of vapor pressure approaches 0.01 S cm^?1.