Evaporación de gotas sésiles en superficies sólidas

JONATHAN M. SCHUSTER; ELIANA M. AGALIOTIS, MARIO R. ROSENBERGER, ALICIA E. ARES, CARLOS E. SCHVEZOV; ALICIA E. ARES Y CARLOS E. SCHVEZOV

Santa Fé

Congreso; Congreso Internacional De Metalurgia y Materiales. Sam ? Conamet / Iberomat / Materia 2014; 2014

sam - Asociación Argentina de Materiales

Ideally, a liquid drop on a flat surface (homogenous, no roughness, rigid and isotropic) form a single and unique contact angle in equilibrium, which value is determined by the interfacial tensions between the liquid drop and the flat solid, the liquid drop and the surrounding vapor and the solid and vapor. The values of these angles could be used to determine the surface tension of the solid. However the value of these angles could change if some evaporation of liquid occurs, particularly in non-saturated atmospheres. Therefore, knowing how the liquid drop evaporates in still air and controlled atmospheric conditions and its effect on contact angle becomes very important in determining the wettability of the solid surface. In the present report the evaporation of water drops is studied when deposited on stainless steel surfaces by digital image analysis, measuring three geometrical parameters: contact angle, drop height and contact radius. The initial contact radius was an experimental parameter and in each case the total surface area and volume where calculated assuming spherical cap. The results show that drops of deionized water on stainless steel evaporated following the spherical cap model with two definite kinetics steps (phase I and II) of the radius evolution. In addition in phase II the contact angle as well as the height has clear different pattern evolutions which are described in this report.