MECHANICAL CONFINEMENT EFFECTS ON THE PHASE SEPARATION MORPHOLOGY OF POLYMER BLEND THIN FILMS

Kari Dalnoki-Veress, James Forrest and John Dutcher,
Phys. Rev. E 57, 5811-5817 (1998).

ABSTRACT

We have measured the phase separation morphology of polystyrene/poly (methyl methacrylate) (PS/PMMA) blend films of thickness h on a silicon oxide (SiO_x) substrate with a SiO_x capping layer. We observe a novel phase separation morphology for small capping layer thicknesses L and a transition from lateral to lamellar morphology as L is increased. We present a simple model which explains the observed lateral morphology and the transition in morphology in terms of a balance between the free energy increase associated with forming the interfaces between PS-rich and PMMA-rich domains and the free energy associated with the elastic bending of the SiO_x capping layer. The simple model reveals the dependence of the transition capping layer thickness L_c on the polymer blend film thickness h, and gives a reasonable quantitative prediction of L_c.

Copyright © 2002, Polymer Surface & Interface Group.
Please contact us for permission to reproduce any material contained in this website.