ON THE SIMILARITY IN THE KINETICS OF SPREADING OF SMALL DROPLETS ON ASOLID-SURFACE

The kinetics of viscous spreading of droplets on a solid surface was s tudied based on the theories of similarity and dimensionalities. The c ases of complete and incomplete wetting under the effect of surface fo rces are considered. Methods to predict the kinetic dependences for th e radius of the wetting perimeter, the wetted surface area, the dynami c contact angle, and the rate of spreading are proposed. The concept o f similarity in the spreading kinetics was extended to the broader cla ss of self-affine processes. The dependence of the kinetics of spreadi ng on the main parameters (droplet volume, shear viscosity, and surfac e tension of a liquid) of the small droplet-substrate-gas system was a nalyzed. The obtained theoretical results were compared with experimen tal data on low-molecular-weight liquids and polymer melts.