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Suppression of Phase Separation Pattern Formation in Blend Films With Block Copolymer Compatibilizer.


pdf icon Suppression of Phase Separation Pattern Formation in Blend Films With Block Copolymer Compatibilizer. (332 K)
Sung, L. P.; Douglas, J. F.; Han, C. C.; Karim, A.

Journal of Polymer Science: Part B: Polymer Physics, Vol. 41, No. 14, 1697-1700, July 15, 2003.

Keywords:

copolymers; thin film; polymer blend; phase separation; surfactant; surface pattern formation; block copolymer; Marangoni pattern

Abstract:

The structure of thin films is sensitive to surface-tension variations that can cause the free surface of films to buckle.14 Many different types of film perturbations cause surface-tension variations and thus film-surface pattern formation. Recent studies2,3 have shown that phase separation within very thin polymer blend films leads to a range of surface patterns (bumps, holes, and labyrinthine ridges and valleys) that depend on the polymer composition. These patterns disappear when the films are returned into the one-phase region of the fluid mixture, verifying their phase-separation origin. 2,3 Although in some situations the surface patterns are beneficial, the surface patterns can sometimes compromise film-barrier properties or create other undesirable changes in polymer-coating properties (optical appearance, friction, tendency to attract impurities from the atmosphere, etc.). This technological problem led us to seek methods of inhibiting surface-pattern formation in thin-blend films.