Morphological transition during the thermal deprotection of poly(isobornyl)-b-poly(1-ethoxyethyl acrylate)

A set of poly(isobornyl acrylate)-block-poly(1-ethoxyethyl acrylate) polymers has been prepared by atom transfer radical polymerization. The 1-ethoxyethyl protecting group can be removed by a mild thermal treatment yielding the poly(acrylic acid) segment. The thin film morphological behavior of selected block copolymers was studied for ex situ as well as in situ deprotected block copolymers using atomic force microscopy (AFM). Low-temperature thermal treatment yielded strongly phase-separated cylindrical features whereas in situ treatment at temperatures above the glass transition temperature of the individual polymer blocks resulted in the initial generation of a similar phase contrast followed by a decrease in phase contrast caused by selective surface enrichment of the more hydrophobic poly(isobornyl acrylate) segment