Alignment of perpendicular lamellae in block copolymer thin films by shearing

摘要: Lamellar block copolymers, with the lamellae standing perpendicular to substrate, are attractive candidates as templates for nanostructure array fabrication. However, no process currently exists impose long-range in-plane alignment of such on simple unpatterned substrates—to align lamellar normal over macroscopic distances. Here, we have generated aligned films in a polystyrene-poly(methylmethacrylate) diblock, PS-PMMA, by neutralizing substrate random terpolymer brush and shearing film moving polydimethylsiloxane (PDMS) pad contact surface. At sufficiently high shear stresses, entire (cm2) area pad; orientation is preserved, although thicker than spacing, “capping layer” PS forms PDMS pad. when compared typical shear-aligned copolymers having morphology cylinders, significantly higher stress required orientational order poorer dislocation density higher; limiting parameter ψ2 ≈ 0.8 achieved at stresses.