Architecture of rod-brush block copolymers synthesized by a combination of coordination polymerization and atom transfer radical polymerization

A combination of coordination polymerization and atom transfer radical polymerization (ATRP) was applied to a novel synthesis of rod-brush block copolymers. The procedure included the following steps: (1) the monoesterification reaction of ethylene glycol with 2-bromoisobutyryl bromide (BIBB) yielded the bifunctional initiator monobromobutyryloxy ethylene glycol and (2) a trichlorocyclopentadienyl titanium (CpTiCl3,; bifunctional initiator) catalyst was prepared from a mixture of CpTiCl3 and bifunctional initiator. The coordination polymerization of n-butyl isocyanate initiated by such a catalyst provided a well-defined macroinitiator, poly(n-butyl isocyanate)bromine (PBIC-Br). (3) The ATRP method of 2-hydroxyethyl methacrylate initiated by PBIC-Br provided rod [poly(n-butyl isocyanate) (PBIC)]-coil [poly(2-hydroxyethyl methacrylate) (PHEMA)l block copolymers with a CuCl/CuCl2/2,2'-bipyridyl catalyst. (4) The esterfication of PBIC-block-PHEMA with BIBB yielded a block-type macroinitiator, and (5) ATRP of methyl methacrylate with a blocktype macroinitiator provided rod-brush block copolymers. We found from the solution properties that such rod-brush block copolymers formed nanostructured macromolecules in solution. (C) 2008 Wiley Periodicals, Inc.