Block copolymers at solid surfaces through physisorbed monolayers of macroinitiators

We report on the radical chain polymerization of n-butyl methacrylate using monolayers of azo-type poly(ε-caprolactone) macroinitiators physisorbed to the surface of planar silicon oxide substrates. In this process block copolymers consisting of poly(ε-caprolactone) and poly(n-butyl methacrylate) (PnBMA) are formed in situ at the surface of the silicon oxide substrate. The preparation of the attached layers and the characterization by surface plasmon spectroscopy (SPS), infrared techniques and water contact angle measurements are described. This “grafting-from” technique can be used to prepare hydrophobic layers on hydrophilic substrates. Following this macroinitiator route some major limitations of the block copolymer physisorption process, such as solubility problems of the block copolymer and intrinsic limitations of the layer thickness can be avoided.