FORMATION OF MICELLES OF CETYL TRIMETHYLAMMONIUM BROMIDE IN WATER-GLYCEROL SOLUTIONS

Abstract

The micellization of cetyltrimethylammonium bromide (CTAB) in glycerol and aqueous solutions of glycerol was studied by means of surface tensiometry. The critical micellar concentration (CMC) was determined at 25 °C and 40 Δ C, and thermodynamic parameters such as the free energy of micellization ΔG°mis, enthalpy ΔH and entropy ΔS of micellization were also measured At 40 °C, CTAB forms micelles in pure glycerol and in the entire range of water-glycerol solutions. For 25 °C, the CMC ranged from 9.2 x 10·4 Min pure water to 8.5 x 10·3M for solutions containing 90% glycerol by volume. The corresponding values obtained/or ΔG° were -4.14 and -2.82 kcal/mole; for ΔH° were -1.03 kcal/mole and -3.73 kcal/mole and for ΔS° were + 10.43 and -3.10 e. u. The addition of glycerol decreases the spontaneity of micelles formation of CTAB in water.