Contact angle interpretation in terms of solid surface tension

Recent experimental (low-rate) dynamic contact angles for 14 solid surfaces are interpreted in terms of their solid surface tensions. Universality of these experimental contact angle patterns is illustrated; other reasons tha t can cause data to deviate from the patterns are discussed. It is found th at surface tension component approaches do not reflect physical reality. As suming solid surface tension is constant for one and the same solid surface , experimental contact angle:patterns are employed to deduce a functional r elationship to be:used in conjunction with the Young equation to determine solid surface tensions. The explicit form of such a; relation is obtained b y modifying Berthelot's rule together with experimental data; essentially c onstant solid surface tension values are obtained, independent of liquid su rface tension and molecular structure. A new combining rule is also derived based on an expression similar to one used in molecular theory; such a com bining rule should allow a better understanding of the molecular interactio ns between unlike Solid-liquid pairs. (C) 2000 Elsevier Science B.V. All ri ghts reserved.