Synthesis and Self-Assembly of Thermotropic Block Copolymer with Long Alkyl Tethered Cage Silsesquioxane in the Side Chain

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 degrees 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 PMMA(175)-bPMAC11POSS(11) (phi PMAC11POSS - 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. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2653-2664, 2011