We investigate the influence of temperature and confinement on surface segregation in thin films of deuterated polybutadiene and polyisoprene near the critical point for phase separation. Neutron reflectivity measurements show that polyisoprene enriches at the air and silicon interfaces in both the 1- and 2-phase regions. A transition between in-plane and surface-directed (layered) phase separation is observed with increasing film thickness. Weak critical adsorption effects cause the blend composition profile to be rounded in comparison with profiles normally measured in small liquid mixtures.
ASJC Scopus subject areas
- Physics and Astronomy(all)