Synthesis of proton conducting phosphonic acid-functionalized polyolefins by the combination of ATRP and ADMET

Abstract

Well-defined copolymers of various compositions possessing polar polyphosphonate brushes precisely placed on an unsaturated polyethylene backbone were obtained by a combination of ADMET and ATRP. Both a macromonomer and macroinitiator approach were explored along with conversion to requisite poly(vinylbenzyl phosphonic acid) (PVBPA)/polyolefin graft copolymers. All polymers were quantitatively deprotected to the corresponding free phosphonic acid-containing PVBPA/polyolefin graft copolymer electrolytes. The thermal behavior and the phase transitions of these materials showed amorphous behavior that was exploited in subsequent proton conductivity experiments. Proton conductivity properties of the PVBPA/polyolefin graft copolymers in anhydrous as well as in humidified conditions reached magnitudes of 10⁻² S cm⁻¹ with particular architectures.