The phase morphologies of designed polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) copolymers were studied at 383, 413, and 443 K by mesoscopic simulations. Eighteen patterned surfaces of four series were designed and designated as "ci", "co", "gra", and rg to study their influence on changing the microscopic phase morphology of copolymers. The topography of the ci series surfaces was shaped by semicircular balls. Different radii were applied to simulate different degrees of surface roughness. The co series were composed of cubic columns as the mask, and the cubic columns were separated by equal spaces. Various sizes and heights of columns were used to simulate different degrees of surface roughness. The gra series were composed of surfaces with different areas of section and the same height to simulate different degrees of surface roughness. The rg series were composed of concentric cuboids with continuous increasing heights and sizes. The degree of phase separation depended on the structures of copolymers, the topography of surfaces and the simulation temperatures. When the triblock copolymer with surfaces induced was composed of the same component at both ends and had larger PS segment percentage, it would present higher values of order parameter, that was, ABA showed the highest, AB the second high and BAB the last, the values of order parameter of the long chains were higher than those of the short ones, except the situation with co-4432 and co-8832 surfaces induced. However, the co-4432 and co-8832 surfaces performed the most intensive extent of inducing effect. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012