The effects of long-ranged and short-ranged forces in confined near-critical polymeric liquids

¹ Department of Physics, University of Surrey - Guildford, UK
² Department of Physics and Astronomy, University of Sheffield - Sheffield, UK
³ ILL, Institute Max Von Laue-Paul Langevin - Grenoble, France
⁴ Hahn-Meitner Institut - Berlin, Germany
⁵ SINQ, Paul Scherrer Institut - Villigen, Switzerland
⁶ ISIS, Rutherford Appleton Laboratory - Chilton, UK
⁷ Fakultät für Physik, Universität Bielefeld - Bielefeld, Germany
⁸ Département de Physique, Université Libre de Bruxelles Boulevard du Triomphe, CP 223, 1050 Bruxelles, Belgium

Corresponding author: msferraz@ulb.ac.be

Received: 19 April 2005
Accepted: 8 July 2005

Abstract

The relative importance of long- and short-ranged forces on the thermal fluctuations at polymer interfaces was investigated with neutron reflection. Polyolefin blends were synthesised to create polymer pairs with a tuned interaction parameter, allowing the exploration of situations from near criticality to strongly immiscible cases in thin-film systems. We have observed for the polymer interfacial width, a transition from a region where long-ranged forces dominate, at higher degree of incompatibility, to a region approaching criticality where short-ranged truncation forces are more relevant.