Collapse of polymer brushes grafted onto planar ... - Wageningen UR

MORPHOLOGIES IN THIN TRIBLOCK COPOLYMER FILMS
K.S. Lyakhova 1) , A. Horvat 2) , G.J.A. Sevink 2) , A.V. Zvelindovsky 1) , R. Magerle 2) ,
J.G.E.M. Fraaije 1)
1)
Soft Condensed Matter Group, Leiden Institute of Chemistry,
P.O. Box 9502, 2300 RA Leiden, The Netherlands
2)
Physicalishe Chemie II, University Bayreuth,
D-95440 Bayreuth, Germany
email: e.lyakhova@chem.leidenuniv.nl
ABSTRACT
The physics behind morphology formation in thin block copolymer films is not well understood. Recent
experiments with free polystyrene- polybutadiene-polystyrene (SBS) films (in collaboration with Bayreuth
University) result in complex morphologies, with terrace formation at integer domain distance film heights and
connecting structures that are not present in bulk. In an article recently published [1], we compared these
experiments with DDFT simulations for a geometry confined between two hard walls and symmetric polymerwall
interaction. We identified two important parameters, the width of the slit and the surface interaction, and
two relevant mechanisms: frustration and surface reconstruction. The experiments and the simulations match
perfectly. In the present study, we extend our simulations to the more general case of asymmetric polymerwall
interactions. The resulting asymmetry in surface reconstruction, combined with frustration, leads to a
much richer phase diagram with many so-called hybrid structures. We compare the results to the symmetric
phase diagram, and identify, similar to the symmetric case, the relevant mechanisms.
Reference
Knoll, A., Horvat, A., Lyakhova, K.S., Kraush, G., Sevink, G.J.A., Zvelindovsky, A.V., Magerle, R., 2002.
Physical Review Letters 89 (3), 035501.