Micro-phase separation of diblock-copolymer melts confined in a slit from simulation calculations - effect of coarse-graining scale

Two methods with different levels of coarse-graining are used to simulate microphase separation in diblock copolymer melts. The first uses Monte Carlo simulation (MC) based on particles and the second uses the cell-dynamical-system method (CDS) based on fluid elements. Results are presented for symmetric and asymmetric A-B diblock-copolymer melts (f(A) = 0.5, 0.4, 0.3 and 0.2) confined in a slit. Several microdomain morphologies are obtained. A lamella structure with alternate A- and B-rich layers appears for the symmetric case. Mesh-like, bi-continuous cylinder-like and dispersed sphere-like layers appear for asymmetric block copolymers with different compositions. Both methods of calculation give similar morphologies, indicating their mutual consistency. However, the calculation efficiency of CDS is remarkably higher, and it is therefore used to provide the pattern evolutions in time, the order-parameter distribution in real space, and the dynamic scattering function in Fourier space. (C) 2004 Elsevier Ltd. All rights reserved.