Chemoenzymatic Approach toward Heterografted Molecular Bottle Brushes

Abstract

Heterografted molecular bottle brushes, i.e., poly(glycidol-graft-e-caprolactone-acetyl)-co-(glycidol-graft-methyl methacrylate) [P(G-graft-CLAC)-co-(G-graft-MMA)] and poly(glycidol-graft-e-caprolactone-acetyl)-co-(glycidol-graft-n-butyl methacrylate) [P(G-graft-CLAC)-co-(G-graft-BMA)] were prepared in two steps starting with a linear polyglycidol. In the first step an approximately 50% homografted polymer poly(glycidol-graft-e-caprolactone-acetyl)-co-glycidol [P(G-graft-CLAC)-co-G] was obtained via ring-opening polymerization of e-caprolactone using polyglycidol as a multifunctional macroinitiator and Novozyme 435 (Lipase B from Candida antarctica (CALB) immobilized on a macroporous resin) as a catalyst. Selective acetylation of the hydroxy groups at the graft ends was achieved via enzymatic acetylation with vinyl acetate, and the hydroxy groups at the backbone were acylated with 2-bromo-2-methylpropionyl bromide. Finally poly(methyl methacrylate) or poly(n-butyl methacrylate) grafts were attached by ato...