Amphiphilic cycloterpolymers of diallyldimethylammonium chloride, diallyloctadecylammonium chloride, and sulfur dioxide

A hydrophilic monomer (diallyldimethylammonium chloride), a hydrophobic monomer (diallyloctadecylammonium chloride), and sulfur dioxide are cycloterpolymerized in dimethylsulfoxide using azobisisobutyronitrile as the initiator to afford water‐soluble cationic polyelectrolytes having a five‐membered cyclic structure on the polymeric backbone. The molecular weights of the polymers containing varying amounts of the hydrophobic monomer (0–7.5 mol %) are determined by light‐scattering experiments. The solution properties of the series of cationic polyelectrolytes are investigated by viscometric techniques. A polymer concentration ( C * HA ) of <1 g/dL is required for the manifestation of hydrophobic associations in these terpolymers containing C 18 hydrophobic pendents. This is a notable improvement over the C * HA values (ca. 15–17 g/dL) for the associating cyclopolymers having a pendant length of C10 to C14. The polymer solutions exhibit a sharp increase in viscosity with increasing polymer concentrations in salt‐free as well as salt‐added solutions. The presence of sodium chloride is shown to enhance the hydrophobic association tremendously. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1298–1306, 2005