Abstract: The equation of the critical surface tension was obtained on the basis of a new equation Young-Verkholomov contact angle. It is established that in the case of wetting of non-polar solids by non-polar liquids (the case of Zisman), the critical surface tension is equal to the corresponding value of the surface energy of the solid.

Abstract: As a result of computational studies, a unique correspondence between the value of θ⁰ and the adhesion force of the solid body σA was established. The transition from the classical Young equation to the equation Young-Verkholomov (from the free surface energy of the solid body σSV to σA) allows us to predict the development of new solid smooth coatings with θ⁰ ≥ 130-135⁰.

Abstract: The isolated system solid / liquid / steam should be considered as a kind of a mechanical system based on the interaction of the forces acting in the system. Within this concept and with the involvement of molecular-kinetic theory the author considered force characteristics at the interface when wetting low-energy smooth solid surfaces. It is shown that the magnitude of the adhesion forces occurring upon wetting between particles (molecules) of liquid placed on a three-phase contact line, and particles on the surface of the solid depends on the surface energy characteristics of a solid body and a liquid. The resulting new equation (Young-Verkholomov equation) of the equilibrium contact angle is

Cosθ₀ = (σ_A - σ_LS) / σ_LV,

where σ_A - the adhesive force at the interface solid/vapor;

σ_LS, σ_LV - surface tension of liquid at the interface liquid / solid phase, and liquid / vapor respectively.

Abstract: It has been shown that on the basic of physical characteristics solid / liquid / vapor system cannot be seen as the thermodynamic. It is a kind of mechanical system. With the use of molecular-kinetic theory we obtain a new equation of the equilibrium contact angle of the following form: Cosθ₀ = (σ_A – σ_LS)/ σ_LV, where σ_A is adhesive force on the surface of a solid boundary with steam; σ_LS, σ_LV is a surface tension force of liquid at the boundaries section liquid/soiid and liquid/vapor phases respectively Based on experimental data we obtained a clear unambiguous relationship between Cosθ₀ and adhesion strength σ_A: error of test point scattering with respect to approximating line does not exceed 1%.

Abstract: Hydrophobic properties of different roofing coatings are studied. It is shown that the value of interfacial angle sufficient to exhibit of a surface unwettability is significantly depended on the temperature of coatings. Water meniscus around the local area with unwettable coating has been obtained experimentally. Height of meniscus for graphite powder coating is ~4.5 mm. The curved surface of the water meniscus have enhanced attraction of dirt and powder fine particles.