Interface width of low-molecular-weight immiscible polymers

The interfacial width between immiscible low-molecular-weight polymer pairs was investigated using neutron reflection. Deuterated polystyrene (d-PS) and poly(methyl methacrylate) (PMMA) polymers of very low molecular weight (Mw) were used. The interfacial width is seen to increase for the low-molecular-weight cases with respect to the 'infinite'-Mw cases. The time dependence of the formation of the interface was also investigated. The results are compared with the predictions of the self-consistent-field theory with a correction based on capillary-wave fluctuations at the interface.