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Determination of Flory–Huggins interaction parameter and self-diffusion coefficients in ternary polymer solutions by quasielastic light scattering

1995; American Institute of Physics; Volume: 103; Issue: 9 Linguagem: Inglês

10.1063/1.470055

1520-9032

Ze Sun, Changling Wang,

Rheology and Fluid Dynamics Studies

We present a new method to determine the Flory–Huggins polymer–polymer interaction parameter and self- (or tracer) diffusion coefficients in a ternary polymer solution made of two monodisperse polymers and a solvent by quasielastic light scattering (QELS). Previously proposed methods based on the random phase approximation (RPA) were restricted to special cases with two polymers having the same molecular weight and identical interaction parameters with the solvent. The present method (also using RPA) has removed these restrictions. It is applicable to an arbitrary ternary solution with polymers having different molecular weight and solvent interaction parameters. To illustrate, we have analyzed the published QELS data of the PDMS/PMMA/toluene ternary system to obtain self diffusion coefficients for each polymer and the Flory–Huggins polymer–polymer interaction parameter as a function of polymer composition in the system.