Surfactants, owing to their amphiphilic architecture, constitute a pivotal class of molecular entities that underpin a wide
spectrum of physicochemical processes in pharmaceutical, industrial, and environmental domains. Their self-assembly into
micelles, bilayers, vesicles, and higher-order mesophases emerges from a finely tuned interplay of noncovalent forces, including
electrostatic repulsion, hydrogen bonding, and van der Waals interactions. A rigorous thermodynamic treatment—invoking Gibbs
free energy minimization, enthalpy–entropy compensation, and the modulation of aggregation equilibria by temperature, pressure,
and ionic milieu—elucidates the driving forces that dictate surfactant behaviour. Phase transitions among micellar, lamellar, and
hexagonal morphologies exemplify the dynamic structural adaptability of these systems, as well as the conditions requisite for their
stability. This framework not only rationalizes practical applications in solubilization, emulsification, bioavailability enhancement,
and surface modification, but also underscores the centrality of surfactant self-assembly in the fabrication of nanoscale
architectures. Nonetheless, extant thermodynamic models remain inadequate in capturing the inherent complexity and
multicomponent heterogeneity characteristic of real-world formulations, thereby necessitating more advanced theoretical and
computational paradigms.
Keywords: Surfactant Thermodynamics, Micelle Formation, Molecular Interactions, Phase Behavior, Bio-surfactants