Critical behavior of a cationic surfactant in an aqueous salt solution

Publisher Website
Google Scholar
Abstract
The critical behavior of a cationic surfactant, butyl‐tetradecyldimethylammonium bromide, in an aqueous 4M–NaBr solution was investigated concerning the isothermal osmotic compressibility and long‐range correlation length by means of light scattering, coexistence curve, and turbidity. The critical exponents were obtained as γ’=1.39±0.04 and ν’=0.70±0.03 together with ξ0=(2.48±0.06) nm, and β’=0.375±0.01. The temperature dependence of turbidity showed a good accordance with the result of light scattering measurement. Negative α’ was obtained from the scaling relation. The critical exponents are in good agreement with the Fisher‐renormalization prediction for the ternary system (almost fully renormalized Ising exponents).