The rate of spread of liquid pools over horizontal solid surfaces and between approaching parallel flat plates

Abstract

Some measurements have been made of the rate of radial spread of liquid pools on horizontal surfaces and between approaching parallel flat plates. Graphs giving the dimensions of the pools after different intervals of time and with different surface finishes have been prepared for several liquids on different kinds of surfaces; also derived graphs relating the rate of radial flow with film thickness, etc., have been included. Movement is complex and specific to the surface and chemical character of the liquid but it is possible to follow the effect of adsorbed surface films and to correlate movement with the periphery resistance (Jamin effect). With the use of binary mixtures of liquids, correlations have been found for rate of radial spread with several properties, such as the coefficient of friction, adhesion, contact angles, and swelling. Any increase in surface activity consequent upon molecular disaggregation is accompanied by a higher rate of movement, increased adhesion, etc. Some liquids are more sensitive to the roughening of surfaces than others. The effect of viscosity usually appears to be masked by surface effects, etc., but with liquids of low Jamin resistance, apart from the initial and later stages of spreading, an approximate relation between time and the radius of the pool can be obtained both for a liquid spreading on a horizontal surface and between approaching parallel plates.