On the generalized concentration and molecular mass dependencies of macromolecular self-diffusion in polymer solutions

Abstract

Self-diffusion experimental data obtained with the n.m.r. pulsed gradient spin-echo method in polyethylene oxide (PEO), polystyrene (PS), dextran, gelatine, cellulose triacetate (CT), poly(dimethyl siloxane) (PDMS) solutions and melts in a wide range of solvents, with molecular mass (M) and concentration (ø), were analysed to show the existence of common dependencies for Ds(M) and Ds(ø). The general law for Ds(ø) is expressed as f( ø \ ̂o) = Ds(ø) L(ø)Ds(0) and is correct for the solvent quality ranging from θ to 'good'. The existence of the generalized f( ø \ ̂o) was examined for the 17 different polymer-solvent systems. With the use of the generalized function, where Ds(O)=lim Ds \ ̂o,Ds(O)≈M-β, \ ̂≈M- 2-β 3 nearly 100 Ds(ø) dependencies were described. The renormalization function L(ø) accounts for the local dynamic properties of the concentration dependence. © 1988