Chuiko M. Control of wetting surfaces of solids by impedance method

The dissertation is devoted to the development of a method for express-control of the degree of wetting a solid surface with liquid for the complex evaluation of the wetting properties of the investigated system "solid - liquid - gas". Based on the analysis of existing methods for measuring the surface tensions of liquids, solids and the Contact Angle, the main approaches for determining the quantitative estimation of parameters characterizing the interaction of contact phases during wetting the solid surface are determined. The paper proposes to use a complex assessment of the wetting qualitative parameters on the basis of the fluid spreading velocity over the solid surface being examined, namely, the rate of change in the spreading area, since this physical quantity depends on wetting the solid surface, the surface tension of the liquid and solids, the viscosity of the liquid, as well as on the state of the solid surface. Developed was, the mathematical model of the wetting process the solid surface with liquid on the basis of the dependence of the Contact Angle on the liquid surface tension and the dielectric properties upon its spreading over the solid surface, which makes possible to implement the control of wetting and spreading by changing the electrical parameters of the system under study. It is proposed to evaluate the degree of wetting solid surface with liquid according to grading scale, which provides a ranking of liquids according to their wetting properties. The points are determined due to the angles of the linearized approximated dependencies of the change in impedance in time when the fluid is spreading. In order to implement the proposed method of control, a design and manufacture of the device was developed. A metrological analysis of the developed instrument on the basis of the concept of uncertainty was carried out, during which the influence factors on the impedance measurement process were analyzed for controlling the degree of wetting and laboratory testing of instrument by control the wetting and spreading process the solid surface with liquid.