VISCOSITY BEHAVIOR OF POLY(GLYCERYL METHACRYLATE) IN THE PRESENCE OF BORATE AND PHENYLBORONATE IONS

The viscosity behavior of polyelectrolyte solutions induced by berate or phenylboronate complexation with poly(glyceryl methacrylate) (PGM) has been investigated. In dilute solutions berate ions can form monodi ol (1/1) complexes and didiol (2/1) intramolecular complexes. Both typ es of complex are anionic. Thus, the polymer is characterized by the e xistence of char ed sites on b the chain and loops formed by intramole cular complexation. On the contrary, phenylboronate can only give mono diol 1/1 complexes. In the presence of passive salt, the charges are s creened. By addition of berate ion to a PGM solution, a decrease of th e initial polymer viscosity due to loop formation is first observed, t hen the anionic charges fixed on the chain by complex formation induce an expansion of the polyelectrolyte and the viscosity of the solution increases. The situation is different for the PGM-phenyl boronate sys tem, where no intramolecular crosslink is present. In this case the vi scosity of the solution increases with phenyl boronate concentration. But for a fixed complexing ion concentration it will tend to that of t he neutral polymer when NaCl is added. (C) 1995 John Wiley & Sons, Inc .