Properties of Ampholytic Surfactant, N-Alkyl-β-alanine

Ampholytic surfactant, N-alkyl-β-alanine, was synthesized and its infrared absorption spectra, surface tension, isoelectric points and critical micelle concentrations of aqueous solutions were measured at various electrolyte concentrations, pH and temperature. The measurements of isoelectric points and infrared spectra confirmed a zwitterionic sructure of N-alkyl-β-alanine. The critical micelle concentrations determined by surface tension measurements are 1.3×10−2 and 9×10−4mol/l respectively for the decyl and dodecyl homologs at 30 °C, the values decreasing with the increase in pH, electrolyte concentration and temperature.