SURFACE-PROPERTIES AND MICELLIZATION IN AQUEOUS-SOLUTIONS OF HOMOLOGOUS SERIES OF CATIONIC SURFACE-ACTIVE MONOMERS

The surface and bulk properties of aqueous solutions of homologous ser ies of cationic surface-active monomers (SAM), derivatives of dimethyl aminoethyl methacrylate, were extensively studied in connection with t he development of the colloidal basis of the nanoencapsulation technol ogy of biologically active substances. Surface tension isotherms sigma (C) at the air-water interface within the temperature range of 25 - 55 degrees C, isotherms of the differential refraction index Delta n(C), density rho(C), and molar heat capacity C-p(C) at 25 degrees C were m easured. Standard values of a free energy entropy and enthalpy of adso rption and micellization as well as values of the increments of the fr ee energies of adsorption (1.2 kJ/mol) and micellization (1.5 kJ/mol) per one CH2-group were determined for the SAM studied. Degree of bondi ng of counterions by the SAM micelles (beta = 0.98) were calculated us ing surface tension isotherms. Isotherms of the apparent variation of solution density Delta rho(C) were calculated in the approximation of additive contribution of various components of SAM solutions to the sp ecific refraction. The values of the increments of molar heat capaciti es C-p per one CH2-group (equal to 13 - 25 J/mol) were found to be in fair agreement with the calculated ones [24].