Synthesis of Poly(p-phenylene)-Poly(4-diphenylaminostyrene) Bipolar Block Copolymers with a Well-Controlled and Defined Polymer Chain Structure

A poly(p-phenylene) (PPP)-poly(4-diphenylaminostyrene) (PDAS) bipolar block copolymer was synthesized for the first time. A prerequisite prepolymer, poly(1,3-cyclohexadiene) (PCHD)-PDAS binary block copolymer, in which the PCHD block consisted solely of 1,4-cyclohexadiene (1,4-CHD) units, was synthesized by living anionic block copolymerization of 1,3-cyclohexadiene and 4-diphenylaminostyrene. To obtain the PPP-PDAS bipolar block copolymer, the dehydrogenation of this prepolymer with quinones was examined, and tetrachloro-1,2-(o)-benzoquinone was found to be an appropriate dehydrogenation reagent. This dehydrogenation reaction was remarkably accelerated by ultrasonic irradiation, effectively yielding the target PPP-PDAS bipolar block copolymer. The hole and electron drift mobilities for PPP-PDAS bipolar block copolymer were both on the order of 10(-3) to 10(-4) cm(2)/V-s, with a negative slope when plotted against the square root of the applied field. Therefore, this bipolar block copolymer was found to act as a bipolar semi-conducting copolymer. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1655-1663, 2011