Thermodynamic parameters of the state
Similar types of non-uniformities can be isolated in various colloidal, including micellar systems, or in other systems of ‘soft materials’, but the number of non-uniformities on their surfaces is much smaller. Different types of non-uniform systems can be sized both macroscopically and small. The above enumeration gives an idea of the complications in describing the surface properties in comparison with the bulk phase, which inevitably arise when considering small systems. For macroscopic non-uniform systems, thermodynamic approaches are possible. The thermodynamic description negates the differences in the properties of the systems under consideration, which can be quite strongly non-uniform in their local properties. Introducing for them the concepts of surface and/or linear tension, thermodynamics reflects the gross effects caused by the presence of a surface, but it does not allow to give a molecular interpretation of these characteristics, and their experimental determination is extremely laborious. Under these conditions, the only method of theoretical description of non-uniform systems is modelling with the help of atomic-molecular models.