Gravity effects on lamellar pattern formation in confined systems

The microphase separation of a diblock copolymer melt in the presence of a gravitational field is simulated by means of a cell dynamical system model. It is found that the presence of hard walls normal to the gravitational he ld is important to the formation of well ordered lamellae. Furthermore, it is found that the formation of lamellae parallel to the hard boundaries and normal to the field correspond to the stable configuration and that the fi eld increases the interface width in the bulk, but the lamella in contact w ith the substrate is strongly segregated. (C) 1999 Elsevier Science B.V. Al l rights reserved.