Kovalchuk V. Dynamic properties of the capillary systems in presence of surfactants

Thesis is devoted to the examination of simultaneously running processes of mechanical and physico-chemical relaxation during rapid deformations of interfaces in capillary systems in presence the surfactants. The attention is focused on the problem of determination of dynamic properties of liquid interfaces in the range of mean and small effective times of adsorption with the maximum bubble pressure method and oscillating bubble method. The theory of rapid modes of bubbles formation or bubble oscillations on thin capillaries in a liquid or surfactant solution is developed and main mechanical, physico-chemical and geometric characteristics are determined, which control the system behaviour depending on experimental conditions. From the analysis of concentration dependences of limiting surface elasticity and characteristic frequency of diffusion relaxation a conclusion is derived about the necessity to take into account the intrinsic compressibility of adsorption layer for correct description of experimental data at large surfactant concentrations. Some specific features of dynamic behaviour of more complicated systems – free liquid films, stabilized by surfactants, wetting films, formed during the transfer of Langmuir monolayers, and foams – are also investigated