One-pot synthesis of grafted brush copolymers via a chain-growth radical/oxidative dual polymerization system

Abstract

This article describes the facile synthesis of grafted brush copolymers via the combination of metal-catalyzed chain-growth radical polymerization and oxidative polymerization, using a dual functional monomer. The most significant finding was the possibility of performing free-radical polymerization and oxidative polymerization in a single step, using copper bromide as a recyclable catalyst. Cu⁺ initiated the radical polymerization via a chain growth mechanism, and Cu²⁺ initiated the oxidative polymerization, leading to grafted brush copolymers in which π-conjugated polymers formed the main chains and poly(styrene sulfonate) (PSS) formed the high-density brushes. Nuclear-magnetic-resonance and Fourier-transform-infrared spectroscopic analyses revealed the formation of poly(thiophene)-co-poly(styrene sulfonate) (PTh-co-PSS) and poly(3,4-ethylenedioxythiophene)-co-polystyrene sulfonate (PEDOT-co-PSS). Ultraviolet and photoluminescence analyses confirmed the formation of the π-conjugated polymers during the dual polymerization process. These grafted brush copolymers had exceptionally good solubilities in N,N-dimethylformamide.