"Click" Incorporation of Radical/Ionic Sites into a Reactive Block Copolymer: A Facile and On-Demand Domain Functionalization Approach toward Organic Resistive Memory

Reversible addition-fragmentation chain transfer polymerization yields reactive block copolymers bearing the pentafluorophenyl ester (PFPA) group, and subsequent Click amidation using 2,2,6,6-tetramethylpiperidine-N-oxyl- and imidazolium-functionalized primary amines produces the corresponding functional block copolymers, leading to installation of statistical radical- and ionic sites into the PFPA segment. The monolayered thin film devices fabricated using the obtained block copolymers exhibit repeatable switching of electric conductivity (on/off ratio > 10³) under a bias voltage, which reveals that the coexistence of radicals and ions in the same spherical domain of the copolymer layer is a prerequisite for repeatable switching memory.