https://doi.org/10.1140/epje/i2011-11051-6
Reversible sphere-to-lamellar wetting transition at the interface of a diblock copolymer system
1
Department of Physics & Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada
2
School of Mathematical and Physical Sciences, University of Reading, Whiteknights, Reading, UK
3
Department of Physics, University of Guelph, Guelph, ON, Canada
* e-mail: dalnoki@mcmaster.ca
Received:
9
February
2011
Revised:
2
May
2011
Accepted:
5
May
2011
Published online:
24
May
2011
We use ellipsometry to investigate a transition in the morphology of a sphere-forming diblock copolymer thin-film system. At an interface the diblock morphology may differ from the bulk when the interfacial tension favours wetting of the minority domain, thereby inducing a sphere-to-lamella transition. In a small, favourable window in energetics, one may observe this transition simply by adjusting the temperature. Ellipsometry is ideally suited to the study of the transition because the additional interface created by the wetting layer affects the polarisation of light reflected from the sample. Here we study thin films of poly(butadiene-ethylene oxide) (PB-PEO), which order to form PEO minority spheres in a PB matrix. As temperature is varied, the reversible transition from a partially wetting layer of PEO spheres to a full wetting layer at the substrate is investigated.
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2011
