Dynamic light scattering of poly(vinyl alcohol)-borax aqueous solution near overlap concentration

The physical properties of PVA-borax aqueous solutions with a PVA concentration near the overlap concentration and various borax concentrations were observed using dynamic light scattering and dynamic viscoelastic measurements. It had been proposed by Leibler et al. that the structure of PVA-borate complex in dilute aqueous solution strongly depends on: (1) excluded volume effect of polymers; (2) the intra- and inter-molecular crosslink reactions between di-diol of PVA and borate ion; (3) the charge repulsion among borate ions bound on the PVA molecules; (4) the screen effect of the free Na+ ions on the negative charge of PVA-borate complex molecules. Based on the experimental data and the model of Leibler et al., the structures of PVA-borate complexes near the overlap concentration in aqueous solutions were proposed. (C) 1997 Elsevier Science Ltd.