Aligned Morphologies in Near-Edge Regions of Block Copolymer Thin Films
Basutkar, M.N.; Majewski, P.W.; Doerk, G.S.; Toth, K.; Osuji, C.; Karim, A.; Yager, K.G. "Aligned Morphologies in Near-Edge Regions of Block Copolymer Thin Films" Macromoleculs 2019
We describe an interesting effect wherein the edge of a block copolymer film becomes aligned. That is, for a discontinuous film, the morphology orients during annealing to become anti-aligned with respect to this edge.
We report a generic phenomenon in the ordering of block copolymer thin films, wherein the morphology spontaneously antialigns with respect to film discontinuities during thermal annealing. The aligned near-edge region propagates further from the edge with increased annealing time and temperature, while also being responsive to heating rate and applied stress fields. This effect is ascribed to a combination energetic preference for morphological orientation at boundaries as well as stress relaxation of the polymer film as it creeps orthogonal to film edges.