Autophobic dewetting of symmetric diblock copolymer films on ordered lamellae

ORAL

Abstract

Autophobic dewetting is the process in which a material retracts from a substrate of the same material. This has been observed for homopolymer melts on brush layers as well as in diblock copolymer systems. In the case of diblock copolymer films, autophobic dewetting can arise above the bulk order-disorder transition temperature due to a gradient of segregation strength induced by the film interfaces. We have measured the contact angle of autophobically dewetting droplets of symmetric polystyrene-b-poly(2-vinyl pyridine) as a function of temperature and the number of ordered lamellae that form the substrate layer. The contact angle decreases monotonically with both temperature and the number ordered lamellae, which can be understood as a dependence on the degree of order at the substrate interface. We compare our experimental results to a self-consitent field theory calculation which includes the decaying order away from the interfaces.

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Authors

  • Mark Ilton

    Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada

  • Pawel Stasiak

    School of Mathematical and Physical Sciences, University of Reading, Whiteknights, Reading, UK

  • Mark W. Matsen

    School of Mathematical and Physical Sciences, University of Reading, Whiteknights, Reading, UK

  • Kari Dalnoki-Veress

    Department of Physics \& Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada, L8S 4M1, Department of Physics \& Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, Canada, Department of Physics \& Astronomy and the BIMR, McMaster University, Hamilton, ON, Canada, Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada, Physics and Astronomy, McMaster University