Amphiphilic molecular brushes with regular polydimethylsiloxane backbone and poly-2-isopropyl-2-oxazoline side chains. 1. Synthesis, characterization and conformation in solution

Abstract

The samples of molecular brushes with a polydimethylsiloxane backbone and side chains of poly-2-isopropyl-2-oxazoline have been synthesized. Regular polydimethylsiloxane with undecene tosylate groups in every fourth siloxane unit was used as a macroinitiator. Two prepared samples are characterized by the same grafting density of side chains, but their different length and copolymer molar mass, 400,000 and 710000 g⋅mol−1. Solution behavior study revealed that macroinitiator and its precursor are flexible-chain polymers and macroinitiator’s thermodynamic rigidity is similar to one of polydimethylsiloxane. It was shown that the conformation of the graft copolymer molecules in a selective solvent resembles a polymer star because of the backbone of molecular brushes is strongly folded and shielded from the solvent by the side chains. The thermoresponsiveness of the synthesized molecular brushes in aqueous solutions has been demonstrated.