Surface and thermodynamic parameters of mixed N-dodecyl N-trimethylsilane ammonium chloride with isooctyl phenol ethoxylate

Isooctyl phenol ethoxylate was mixed with N-dodecyl-N-trimethylsilane ammon ium chloride and N-hexadecyl-N-trimethylsilane ammonium chloride, respectiv ely. The surface tensions of aqueous solutions of cationic-nonionic mixture s were measured as a function of nonionic concentration at 35 degrees C wit h constant cationic concentration. By using the Hutchinson method, the surf ace excess concentrations, surface mole fractions, and interaction paramete rs of binary surfactant mixtures were calculated. A synergistic effect for reducing surface tension was observed for adsorption at the surface at low concentrations of N-dodecyl-N-trimethylsilane ammonium chloride.