s From Fundamental Properties to Applications of Surface Activity Investigations: The Kinetic and Thermodynamic Aspects

Interfaces, or surfaces in particular (fluid-solid interfaces), are the boundary limits of two immiscible phases characterized by the surface free energy. Getting insight into their fundamental property is of great importance for both scientific and industrial activities. Such an approach enables us to control the formation and stabilization of colloidal systems, which consist of producing homogenous dispersions from at least two initially immiscible phases. In this mini-review, the kinetic and thermodynamic aspects of fluid surfaces are overviewed. Successively, the main phenomena occurring at the interfaces and the appropriate methodology of investigations, the role of amphiphilic molecules in modifying surface properties and generating various functionalities as a function of their chemical structure, size, and shape, and the current approaches for characterizing interactions as well as synergism or antagonism within mixed systems are treated. Relevant relationships of dynamic fundamental properties to macroscopic consequences at the solid and fluid interfaces of single and mixed amphiphile systems are illustrated.