Yoav Tsori

A simple model to interpret the orientation transition seen in block copolymers (BCP) systems in contact with rough substrates was described. The amplitude of sinusoidal variation, φ ₀, depends on the degree of segregation and vanishes at the order-disorder temperature (ODT). It was found that the accumulated frustration of parallel lamellae leads to their relative instability toward the perpendicular phase. The transition between parallel and perpendicular lamellae is expected to be at q _sR ∼ 1 and independent of q ₀.