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Dimensional Crossover in the Phase Separation Kinetics of Thin Polymer Blend Films.


pdf icon Dimensional Crossover in the Phase Separation Kinetics of Thin Polymer Blend Films. (176 K)
Sung, L. P.; Karim, A.; Douglas, J. F.; Han, C. C.

Physical Review Letters, Vol. 76, No. 23, 4368-4371, June 3, 1996.

Available from:

FOR MORE INFORMATION CONTACT: URL: http://link.aps.org/abstract/PRL/v76/p4368

Keywords:

kinetics; polymer blend films

Abstract:

The kinetics of phase separation in thin polymer blend films of polystyrene and polybutadiene on a silicon substrate is examined by optical microscopy of the free film boundary. Our observations on 1000 and 200 films are consistent with a crossover from three- to two-dimensional spinodal decomposition kinetics in the (off-critical) viscous hydrodynamic regime. In this stage of phase separation the exponent n, characterizing the scale R(t)~tn of the coarsening pattern, is predicted to change from 1 to a value near 0.46 upon lowering the dimensionality.