Synthesis and Characterization of an ABC Miktoarm Star Terpolymer of Cyclohexadiene, Styrene, and 2-Vinylpyridine

Abstract

The three arms of the novel ABC mixed-arm star terpolymerdescribed herein were chosen purposefully to create, uponexposure to a silica or mica surface, a conformationallyasymmetric binary brush having a P2VP “anchor” block withboth PS and high 1,4-PCHD “buoys”. The chemical dissimilarityof the arms and the short-term longevity of poly(cyclohexadi-enyl) macroanions combine to pose a difficult synthetic chal-lenge. For example, the cyclohexadiene block needs to besynthesized in nonpolar media without the presence of P2VPas polar components complicate both control of the PCHD anionstability and the resultant microstructure of the PCHD polymerobtained. In contrast, polymerization of 2-vinylpyridine is mostsuccessfully achieved in tetrahydrofuran (THF) at low temper-atures, so switching of polymerization media during thesynthesis was required.The target polymer was sought through the use of a1,1-diphenylethylene (DPE)-based strategy as shown in Scheme1. Employing anionic polymerization techniques previouslydetailed,