Melt brushes of diblock copolymer
Department of Mathematics, University of Reading, Whiteknights, RG6 6AX, Reading, UK
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Accepted: 5 May 2009
Published online: 24 June 2009
Using self-consistent field theory (SCFT), we investigate the morphologies formed by a melt brush of AB diblock copolymers grafted to a flat substrate by their B ends. In addition to a laterally uniform morphology, SCFT predicts three ordered morphologies exhibiting different periodic patterns at the air surface: a hexagonal array of A-rich dots, an alternating sequence of A- and B-rich stripes, and a hexagonal pattern of B-rich dots. When the phase diagram of the tethered film is plotted as a function of A/B incompatibility, N , and diblock composition, f , it resembles the bulk phase diagram with the periodic phases converging to a mean-field critical point at weak segregation. The periodic-phase region in the phase diagram shrinks with increasing grafting density and expands when the air surface acquires an affinity for the grafted B blocks.
PACS: 82.35.Jk Copolymers, phase transitions, structure – / 81.16.Rf Nanoscale pattern formation – / 68.47.Pe Langmuir-Blodgett films on solids; polymers on surfaces; biological molecules on surfaces –
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2009