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Control of self-assembly in block-copolymer nanofilms

Dr. Irina Neratova, Universität Ulm

24.01.2012 11:00 Uhr
Seminarraum 04.16, Raumnr. 3001

The well-defined nanostructures with long-range order are technologically and industrially important. Because of the self-assembly into periodic arrays block copolymers (BCP) form films with different patterns. For many applications where regular periodic arrays are required, it is necessary to generate specific alignment of the nanostructures in block copolymer films. Conventional lithography techniques are not suitable and disadvantageous because of multistep process, which makes them very slow and high cost for large-area applications at high densities.

The unconventional approaches based on self-assembly of BCPs have been suggested using mesoscopic simulation methods such as dissipative particle dynamics and dynamic density functional theory. We study the self-assembly of the cylinder-forming and lamellar-forming copolymer films near patterned surfaces (hexagonal, sparse rectangular and spare triangular patterns), having periodically distributed regions of different wettability. The parallel alignment of microdomains between preferentially attractive homogeneous surfaces is shown to transform into the stable perpendicular hexagonal phase in the case of the substrate patterns, which commensurate with the hexagonal morphology in the bulk. The new strategy based on double phase separation of the binary mixture of copolymers is suggested. The role of a solvent in the self-assembly of block copolymer in films have been shown.