PREFERENTIAL WETTING OF OLIGOMERIC ETHYLENE-GLYCOL PROPYLENE-GLYCOL BLENDS ON SOLID-SURFACES

The phase separation of oligomeric ethlyene glycol/propylene glycol sy stems was investigated by light scattering in the presence of a solid surface. Beside the spinodal decomposition in the bulk of the system, a wetting transition was observed when phase separation occurred at co nditions near the maxima of these phase diagrams. The transition was d etected as a light scattering halo, which is more intense at a composi tion which does not coincide with the critical one. This composition d oes not depend on the surface but the halo intensity is higher when gl ass is used instead of PVC.