On the microscopic parameters at a moving contact line during wetting process

Abstract

The velocity of wetting a droplet on solid surface is a function of dynamic contact angle formed at a point on the contact line of solid and liquid phases. In this paper, the velocity of wetting obtained using the Arrhenius empirical equation is related to that of the dynamic contact angle. The resulting relationship, however, introduces two microscopic parameters, namely microscopic displacement frequency and length, which are not known as a priori and are usually obtained using a curve-fitting of the measured data. A general correlation for the microscopic displacement frequency which has a wide range of variations is developed that is only a function of the known values of a wetting process. This correlation is presented by improving the available correlation for the surface component of the specific activation free energy of a wetting process using a curve-fitting of a wide range of experimental data. The predicted values from the correlation are in good agreement with those of the reported experiments even when a rough estimate value for the microscopic displacement length is used.