Dewetting properties of polystyrene homopolymer thin films on grafted polystyrene brush surfaces

We have found that the critical molecular weight for auto dewetting of a homopolymer on a polymer brush of the same chemical composition is approximately N_H = 0.5 N_B, in good agreement with the mean field theory prediction. The measured velocity on the brush surface is at least an order of magnitude faster than that of the polystyrene (PS) on a homopolymer interface, with a greatly decreased dependence on the PS molecular weight. This suggests slippage as a possible mechanism for the dewetting dynamics.