Block copolymers consist of chemically distinct polymer chains (blocks) covalently bonded together. Due to the differences in the physiochemical properties of these blocks, the block copolymers undergo order disorder transitions (ODT) at the microscopic level, resulting in microphase-separated states. The presence of these microscopic structures has significant impact on the technological applications of block copolymers in the field of nanofabrication, copolymer-based lithography and photonic materials.

Diblock copolymers exhibit a variety of microstructures, which depend on the relative compositions of the two distinct blocks. In case of symmetric diblock copolymers, the equilibrium structure is the lamellar structure where each lamellar layer is an A-B or B-A repeat unit. We use Interfacial-SAFT (iSAFT) density functional theory to study the morphologies of symmetric diblock copolymers confined between two parallel surfaces, both of which selectively attract one component of the diblock. The effect of the film thickness on the microstructure has been investigated.