THERMODYNAMIC INTERACTION PARAMETERS IN POLYMER-SOLUTIONS AND GELS

Polymer-solvent interaction parameters are reported for poly(vinyl ace tate)-acetone, poly(vinyl acetate)-toluene, and poly(dimethyl siloxane )-toluene systems using different techniques. Results obtained by osmo tic deswelling are compared with those from quasielastic light scatter ing and small-angle neutron scattering (SANS). In gels, the latter tec hniques involve separation of the time-dependent from the static compo nent of the scattered radiation. Separation is achieved in quasi-elast ic light scattering through the heterodyning properties of the light, and in SANS by subtracting an appropriate static structure factor. The interaction parameters obtained by different separation procedures ar e consistent with measurements using the osmotic method. (C) 1995 John Wiley & Sons, Inc.