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)] 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 block‐type macroinitiator provided rod–brush block copolymers. We found from the solution properties that such rod–brush block copolymers formed nanostructured macromolecules in solution.