SELF-ASSEMBLY OF A HOMOPOLYMER MIXTURE VIA PHASE-SEPARATION

We propose a mechanism for creating lateral order in thin films of a h omopolymer mixture via spinodal decomposition in the presence of a lat erally structured substrate surface. The system under consideration is a mixture of deuterated polystyrene and partially brominated polystyr ene (PBr(x)S, x=0.5) spuncast onto different substrates from toluene s olution. We demonstrate that periodic stripe-like domain structures ca n be observed in the polymer films after spinodal decomposition on a p eriodic array of Cr lines on a H-terminated Si surface. The effect van ishes when the chemistry of the underlying structure is changed, stron gly indicating an interface-driven ordering of the polymer film.