Sudhakar Puvvada

Molecular‐thermodynamic approach to predict micellization, phase behavior and phase separation of micellar solutions. I. Application to nonionic surfactants

We present a detailed description of a molecular‐thermodynamic approach which consists of blending a molecular model of micellization with a thermodynamic theory of phase behavior and phase separation of isotropic (surfactant–water) micellar solutions. The molecular model incorporates the effects of solvent properties and surfactant molecular architecture on physical factors which control micelle formation and growth. These factors include (i) hydrophobic interactions between surfactant hydrocarbon chains and water, (ii) conformational effects associated with hydrocarbon‐chain packing in the micellar core, (iii) curvature‐dependent interfacial effects at the micellar core–water interface, and (iv) steric and electrostatic interactions between surfactant hydrophilic moieties. The free energy of micellization gmic is computed for various micellar shapes Sh and micellar‐core minor radii lc. The ‘‘optimum’’ equilibrium values, l*c, Sh*, and g*mic, are obtained by minimizing gmic with respect to lc and Sh. The...

Molecular-Thermodynamic Approach to Predict Micellar Solution Properties

In this paper we present a conceptual overview of our recently developed molecular-thermodynamic approach to predict micellization, thermodynamic properties, and phase separation of micellar solutions. A detailed exposition may be found in Ref..

Molecular Modelling of Micellar Solutions

We review a recently developed molecular-thermodynamic approach which consists of blending a molecular model of micellization with a thermodynamic theory of phase behavior and phase separation of isotropic micellar solutions. The molecular model incorporates the effects of surfactant molecular architecture and solvent properties on the physical factors which control micelle formation and growth. The approach can predict whether the micelles that form are spheroidal, cylindrical, or disc-like in shape. The approach is also capable of predicting micellar solution properties as a function of surfactant concentration and temperature. These properties include (i) critical micellar concentration, (ii) micellar size distribution and its characteristics, (iii) critical surfactant concentration for the onset of phase separation, and (iv) other thermodynamic properties such as the osmotic compressibility. The molecular- thermodynamic approach provides an accurate description of a wide range of experimental findings in aqueous micellar solutions of nonionic surfactants belonging to the polyoxyethylene glycol monoether family.