Dimensional Crossover in the Phase Separation Kinetics of Thin Polymer Blend Films.
Dimensional Crossover in the Phase Separation Kinetics
of Thin Polymer Blend Films.
Sung, L. P.; Karim, A.; Douglas, J. F.; Han, C. C.
Physical Review Letters, Vol. 76, No. 23, 4368-4371,
June 3, 1996.
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kinetics; polymer blend films
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.