Surface and Interface Properties and Associated Behavior in Water and Brine Solutions of an Acrylamide-Based Terpolymer with a Macromonomer

Abstract

A novel macromonomer, p-vinylbenzyl-terminated octylphenoxy poly(ethylene oxide) (VBE, polymerization degree: 24), was copolymerized with acrylamide (AM) and sodium 2-acrylamido-2-methylpropane-sulfonate (NaAMPS) to form a water-soluble terpolymer (abbreviation: PAAB). It exhibited remarkable surface and interface activities as well as a thickening effect in unsalted and brine solutions. The variation of surface and interface tensions with NaCl concentration was investigated; the interface tensions in water and in a 70 g L−1 NaCl solution were, respectively, 4.1 mN m−1 and 2.3 mN m−1 at a polymer concentration of 0.1 g dL−1. The intermolecular hydrophobic associations in unsalted and brine PAAB solutions as a function of polymer concentration and the conformation of polymer chains were characterized by a fluorescent probe. The results indicated that the incorporation of long side chains could expand the polymer chains in brine solutions as well as in the unsalted solutions. The probe investigation in the unsalted and brine polymer solutions also showed that the extended monomolecules were dominant at the polymer concentrations lower than 0.05 g dL−1 and that the intermolecular hydrophobic associations were enhanced sharply above the critical association concentrations of 0.10 g dL−1.