REMARKS ON THE STRUCTURE AND VALIDITY OF THE CAHN-HILLIARD-COOK THEORY IN MULTICOMPONENT POLYMER SYSTEMS

The accuracy of the linear Cahn-Hilliard-Cook (CHC) theory in matrix f orm (multicomponent description) is scrutinized by comparing its exact macroscopic derivation with its phenomenological derivation based on the linear Markov process assumption. The effect of the coupling of de nsity modes to those which are not directly observed is examined. The influence of the initial state on the accuracy of the CHC theory is di scussed. Interpretation of scattering experiments using a bimodal desc ription of transients is presented in detail. As an application, the p ossible effect of coupling to viscoelastic modes on transients is anal ysed. (C) 1997 Elsevier Science Ltd.