Synthesis and self-assembly of thermotropic block copolymer with long alkyl tethered cage silsesquioxane in the side chain

Abstract

Thermotropic POSS-containing poly(methacrylate) with long alkyl chain tethered polyhedral oligomeric silsesquioxane (POSS) in the side chain and the block copolymers (PMMA-b-PMAC11POSS) were developed by through living anionic polymerization. The resulting polymers indicated a phase transition temperature at 112 °C from spherocrystal to isotropic phase. The POSS-containing polymer segments tended to form matrix of microphase-separated nanostructures in the bulk even in the very low volume fraction, for instance, PMMA cylindrical nanostructure was obtained by PMMA175-b-PMAC11POSS11 (ϕPMAC11POSS = 0.44). The control of thin film morphology was carried out by not only solvent annealing, but also thermal annealing, resulting in the formation of well-ordered dot- and fingerprint-type nanostructures. This is the first report in a series of POSS-containing block polymers that are capable for thermal annealing to generate well-ordered microphase-separated nanostructures in thin films. The novel thermotropic POSS-containing block copolymer offers a promising material for block copolymer lithography. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011