Hydrophobically modified polyelectrolytes I. Dilute solution properties offluorocarbon-containing poly(acrylic acid)

Dilute solution viscosity of fluorocarbon-containing hydrophobically modifi ed poly(acrylic acid) was measured in aqueous solutions of various NaCl con centrations. The intrinsic viscosity ([eta]) and Huggins coefficient (k(H)) were evaluated using Huggins equations. It is found that, at low NaCl conc entration, the modified polymers exhibit values of intrinsic viscosity ([et a]) and Huggins coefficient (k(H)) Similar to those of unmodified polymers. For both of the modified and unmodified polymers, the intrinsic viscosity decreases with increase of NaCl concentration, while the Huggins coefficien t increases upon addition of NaCl. But the variation of [eta] and k(H) is m ore significant for the modified polymers, which reflects the enhanced intr a- and intermolecular hydrophobic association at higher NaCl concentration.