Suppression of Phase Separation Pattern Formation in Blend Films With Block Copolymer Compatibilizer.
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899