Formation of micelles of cetyltrimethylammonium chloride and cetyltrimethylammonium bromide in N-methyl acetamide—alcohol and N,N-dimethyl acetamide—alcohol mixtures

The critical micelle concentrations of cetyltrimethylammonium chloride and cetyltrimethylammonium bromide in solutions of in N-methylacetami de and in N,N-dimethyl acetamide with added methanol, ethanol, n-propanol, n-butanol and n-pentanol were determined using electrical conductivity and surface tension measurements at various temperatures. Both methods show that micelles are formed in N-methyl acetamide and N, N-dimethyl acetamide solutions in a presence of n-alcohols. Critical micelle concentrations were also determined as functions of concentration of added alcohol. The data suggest that alcohol adding leads to an enhancement of penetration of alcohol into the micelle external shell that depends on the alcohol chain length. Thermodynamic parameters for micellar systems in a presence of n-alcohols were also calculated.