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A chemical pattern on a substrate is transposed into thin films of a ternary polymer blend during spin-casting from a common solvent. One of the blend components intercalates at interfaces between the other two phases to reduce their interfacial energy. As a result, an extensive substructure is formed, in addition to domains with pattern periodicity lambda. Morphologies with well-ordered lateral domains are created not only when the inherent scale of the phase domains R is comparable to lambda (as observed previously) but also for R similar to lambda/2, extending pattern transposition to smaller length scales.

We have measured the surface segregation towards the vacuum in films of a binary mixture of deuterated E48EE52 (d52)—and hydrogenous E38EE62 (h66)—random olefinic copolymers. Here E and EE are the linear ethylene and branched ethyl ethylene groups (C4H8) and [C2H3(C2H5)], respectively. The d52 copolymer is enriched at the surface when d52 is the minority component in the blend. On the contrary, the surface is depleted in the d52 chains, when they constitute a majority of the mixture. We have determined two branches of the segregation isotherm corresponding to the enrichment and the depletion. A mean-field Cahn model describes consistently these two isotherm branches. The observed enrichment-depletion duality modifies a common viewpoint on surface segregation.

We have studied the surface-induced spinodal decomposition in thin films of deuterated and protonated polystyrene, using 3He nuclear-reaction analysis and dynamic secondary-ion mass spectroscopy. We found that the amplitude of this process may be modified by a polyisoprene-polystyrene diblock copolymer, which segregates predominantly to the surface when admixed to the isotopic polystyrene blend. This is due to the reduced surface attraction of deuterated polystyrene for the increased surface coverage by diblocks. Finally, the surface directed mode of the spinodal decomposition is observed to be extinct for the surface completely covered by copolymers.