Physicochemical studies on microemulsions IV-A comprehensive estimation of the energetics

Abstract

A comprehensive presentation of the proposed thermodynamic theories on microemulsion formation has been made. The thermodynamic functions (parameters) viz. van der Waals potential, configurational entropy, potential energy and droplet free energy in water-in-oil microemulsion stabilized by the amphiphiles aerosol OT, sodium dodecyl sulphate, cetyltrimethylammonium bromide, butanol and hex-ylamine have been evaluated. The estimated van der Waals potential has been found to be much lower than the critical phase separation value of 10.6. Inter droplet interaction leading to amphiphile penetration has been considered to be responsible for this effect. It has been observed that the effective surfactant chain length has significant effect on the droplet free energy and the potential energy. The hydrodynamic radius of the microwater droplets has been found to be inversely proportional to the configurational entropy.