Microphase separation of mixed polymer brushes physisorbed on cylindrical surfaces

Abstract

We present a self-consistent field theoretical study of phase separation in binary polymer brushes physisorbed on cylindrical surfaces under good solvent conditions. In agreement with earlier simulation and experimental work, we find that macrophase separation occurs for two immiscible polymers of the same length, while a chain length mismatch between two polymer types promotes microphase separation, with ring-shaped alternating stripes forming perpendicular to the cylinder axis. We observe that the width of the stripes increases with increasing immiscibility, increasing substrate curvature, decreasing mismatch in the chain length, and decreasing the amount of adsorbed polymer. We rationalize these observations by analyzing entropic and energetic contributions to the Helmholtz free energy of the system.