The influence of surface grafting on the growth rate of polymer chains

The effect of surface grafting on growth kinetics during controlled radical polymerization (CRP) was investigated by comparing the growth of polymers in solution with that on a flat silicon surface. The surface-grafted polymers were attached to the surface via a photo-cleavable initiator, which allowed the polymers to be detached by means of UV light with a wavelength that did not lead to polymer photolysis. The molecular weights of surface- and solution-grown polymers were determined by size-exclusion chromatography (SEC). It could be shown that for a series of polymers synthesized from alkyl methacrylate monomers, it was principally the grafting density that determined the ratio of the molecular weight on the surface to that in solution.