Synthesis and solution properties of amphiphilic cyclopolymers and terpolymers of 4-methoxycarbonyl-1, 1-diallylpiperidinium chloride, diallyloctadecylammonium chloride, and sulfur dioxide

The cycloterpolymerization of a hydrophilic monomer, 4-methoxycarbonyl-1,1- diallylpiperidinium chloride, with a hydrophobic monomer, diallyloctadecylammo- nium chloride (3-7 mol %), and sulfur dioxide in dimethyl sulfoxide with azobisisobutyronitrile as the initiator afforded a series of water-soluble cationic polyelectrolytes (CPEs) at well over 90% yields. Acidic (HCl) hydrolysis of the ester groups in CPEs to CO₂H groups gave the cationic acid salts (CASs), which on treatment with 1 equiv of NaOH, furnished polyzwitterions (PZs). Contrary to the well-known behavior that the normal PZs are only soluble in brine, PZ in the absence of the hydrophobe was found to be soluble in salt-free water. The solution properties of the resulting series of interconvertible polymers (CPE → CAS ⇋ PZ) were investigated by viscometric techniques. At a shear rate of 0.36 s^-1, 2 g/dL solutions of CPE having 0, 3, 5, and 7 mol % hydrophobe in salt-free water at 30°C were found to have apparent viscosity values of 4000, 164,000, 670,000, and 1,430,000 cps, respectively. Polymer-surfactant interactions were investigated with the cationic surfactant cetyltrimethylammonium bromide (CTAB). Tremendous increases in the viscosity values of the CPE having 7 mol % of the hydrophobe were observed in the presence of the surfactant at a shear rate of 0.36 s _-1; a 0.75 g/dL solution of the polymer in salt-free water was found to have apparent viscosity values of 18,000 and 235,000 cps in the absence and presence, respectively, of 3 mM CTAB.