Berlin 2015 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Interfaces and Thin Films II (joint session with CPP)
DS 18.2: Vortrag
Dienstag, 17. März 2015, 14:30–14:45, C 243
Simulations of solvent vapor annealing of cylinder-forming blockcopolymer thin films — •Anatoly V. Berezkin1, Igor I. Potemkin2, and Christine M. Papadakis1 — 1Technische Universität München, Physik Department, München, Germany — 2Lomonosov Moscow State University, Physics Department, Moscow, Russian Federation
Ordered block copolymer films are promising as functional templates for lithography, molecular biology, colloid science etc. Using dissipative particle dynamics, we simulated the solvent vapor annealing (SVA) that is used to relax morphological defects, and control domain orientation in these films. The drying of films was considered in case of intermediate A/B block segregation and fast solvent evaporation. Under these conditions, the SVA transforms equilibrium morphology of lying cylinders to hexagonally ordered perpendicular cylinders in the wide parameter range. The best conditions for this were a moderate initial solvent concentration in the film, and a selectivity of the solvent to the major block. This is probably necessary to compensate entropy-driven adsorption of the short blocks at the film surfaces, revealed in other works. Too weak or too strong block segregation, or solvent selectivity result in disordered morphologies. First disordered microdomains are formed, and than after evaporation of the half of the solvent, the domains reorient along the gradient of solvent concentration. This may be explained by the Gibbs-Marangoni effect. Such mechanism of microdomain ordering notably distinguishes from those observed in other recent simulations.