Evaluation of Wettability from Capillary Rise between Filaments

Abstract

Measurements of the liquid capillary rise between filaments mounted in the form of a vertical “V” are reported and their consequences discussed. At a critical spacing between the filaments, there is a configurational change in the rise, analogous to the onset of wicking action in parallel horizontal filaments. This critical spacing may be used as a relative index of wettability. The wettability of nylon and polypropylene filaments in a series of liquids is compared to illustrate the method. A thermodynamic derivation of the relation between capillary rise and spacing at less than the critical spacing is discussed.