Temperature, composition and molecular-weight dependence of the binary interaction parameter of polystyrene/poly(vinyl methyl ether) blends

Abstract The binary interaction parameter χ eff has been obtained for deuterated polystyrene/poly(vinyl methyl ether) blends as a function of temperature, composition and molecular weight from small-angle neutron scattering experiments. The consistency of the correlation length ξ, the zero-wavenumber scattering intensity S (0) and the χ eff parameter with the mean-field prediction has been demonstrated by the q dependence of the static structure factor S ( q ) and the 1/T dependence of ξ −2 , S (0) −1 and χ eff . The effective interaction parameter χ eff can be related to the Flory-Huggins interaction parameter χ eff can be related to the Flory-Huggins interaction parameter χ F . The free-energy function as well as the spinodal curve and cloud-point curve have been constructed.