Amphiphilic block copolymers comprising poly(ethylene oxide) and poly(styrene) blocks: synthesis and surface morphology

Monofunctional PEO-macroinitiators (mPEO-F) were prepared from monohydroxyfunctional poly(ethylene oxide)s and 2-chloro-2-phenylacetylchloride. In order to synthesise poly(ethylene oxide)-block-poly(styrene) (PEO-b-PS) the macroinitiators were applied to the atom transfer radical polymerisation (ATRP) of styrene in the bulk. Well-defined block copolymers were obtained with predetermined molecular weight and narrow molecular weight distribution. Kinetic aspects of ATRP of styrene depending on the molecular weight of the macroinitiator are discussed. Surface analysis by means of atomic force microscopy in tapping mode using phase imaging reveals characteristic morphologies as a function of the volume fraction of PEO. The higher the PEO content the more PEO is found at the polymer/air interface. The preparation of the samples has a main impact on the observed morphology. The polymer films are hygroscopic and alter their morphology being exposed to air.