Role of surface‐active materials (amphiphiles and surfactants) in the formation of nanocolloidal dispersions, and their applications

Amphiphiles and surfactants are surface-active molecules with special properties at interfaces, and they can undergo different modes of self-association forming colloidal entities in solution. They can also stabilize other colloidal dispersions including nanoparticles, and help the formation and protection of nanodispersions resulting from chemical reactions. In this study, we have discussed the formation, properties, and applications of such nanocolloid-like species formed in solution by different methods with special stress on various types of surfactants. Nanoparticles show the difference in melting point, electrochemical properties, conductance, etc., from their corresponding bulk material. Classical thermodynamics is used to explain this property. The basics of such processes, their types, morphology, stability, and usefulness have been presented and discussed. The types of assemblies that arise from the self-associations of the amphiphiles, and surfactants under different conditions (i.e., micelles, reverse micelles, vesicles, liposomes, niosomes, etc.) have been also presented. Examples of their types, morphologies, transformations, and applications in relation to the stability, and functions of nanodispersions or nanocolloids are exemplified with multiple illustrations from earlier as well as recent research. The use of biosurfactants and block copolymers is also discussed. The stabilization of nanoparticles by "capping" has been discussed in some detail. A short account of the hydrothermal and solvothermal processes of synthesis of nanomaterials using amphiphiles as templates has been also presented. The multiple applications of amphiphile-mediated nanoscience have been briefly presented and discussed.