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Morphology of Symmetric Diblock Copolymers Confined Between Two Stripe‐Patterned Surfaces – Tilted Lamellae and More
Author(s) -
Wang Qiang
Publication year - 2005
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.200400062
Subject(s) - lamellar structure , perpendicular , materials science , monte carlo method , morphology (biology) , surface (topology) , optics , copolymer , condensed matter physics , confined space , thin film , geometry , physics , nanotechnology , composite material , chemistry , geology , polymer , paleontology , statistics , mathematics , organic chemistry
Summary: We report the first Monte Carlo simulations on the thin‐film morphology of symmetric diblock copolymers confined between either symmetrically or antisymmetrically stripe‐patterned surfaces. Under suitable surface configurations (where the lamellae can comply with the surface patterns and can have a period close to the bulk lamellar period L 0 ), tilted lamellae are observed for film thicknesses D ≥ 2 L 0 ; the checkerboard morphology is obtained for smaller film thicknesses. The A‐B interfaces in the tilted lamellae are basically perpendicular to the surfaces in their immediate vicinity, and exhibit undulations away from them. In some cases, the severe frustration imposed by the two patterned surfaces leads to irregular or unexpected morphologies, which represent locally stable states. The efficient sampling of our expanded grand‐canonical Monte Carlo technique enables us to observe more than one locally stable morphologies and the flipping between them during a single simulation run.Tilted lamellae between symmetrically patterned surfaces (perpendicular to z ) with a surface pattern period of 1.5 L 0 and a film thickness of 2.67 L 0 . L 0 is the bulk lamellar period and the black curves mark the A‐B interfaces.