We experimentally examined the scaling relationship between correlation length ~ and polymer concentration c in homogeneous gels at swelling equilibrium. Polyacrylamide gels having various crosslink densities were synthesized and brought to swell in water/acetone mixtures with various mixing ratios. Their correlation lengths ~ were determined by small-angle X-ray scattering. A -3/4 power law (~ oc c-3/4) was found for the gels swollen in pure water, where c varied with the crosslink density as expressed by r in the as-prepared state. Here r denotes the ratio of the concentration of the monomer to that of the bifunctional monomer at the stage of specimen preparation. On the other hand, a -1/3 power law (~occ-1/3) was obtained for the gels having similar values oft when swollen in water/acetone mixtures with various mixing ratios. Both of the power laws are in accord with the predictions given by the c* theorem introduced by de Gennes for a homogeneous gel swollen in a good solvent.
Посилання на статтю:
Scaling analyses of polyacrylamide gels at swelling equilibrium in water/acetone mixtures by small-angle X-ray scattering / Shinichi Sakurai and Hisao Hayashi // Polymer. – 1993. – Vol 34. – P. 4625-4628.