Spinodal decomposition-like patterns via metastable state relaxation

The slow demixing of block copolymer thin films in relief domains is interpreted as a two-dimensional phase transition kinetics following a quench into a biphasic region of a phase diagram. The associated scalar parameter {Ψ} is a linear function of the local thickness of film. Two samples with critical {Ψ}'s have been experimentally studied by atomic force microscopy. At long times, the two stable phases draw spinodal decompositionlike patterns. At shorter times, the existence of an additional metastable phase is demonstrated and explained.