1988 Volume 52 Issue 1 Pages 43-49
A method is described for measuring the surface tension and the contact angle by a new fitting method for experimental measurements of the contour of sessile drop. In the present method, more than one hundred of experimental points were read on the photographical contour in order to improve the accuracy. And an extension of the Newton-Raphson method was made for prevention of the increasing disconvergence with the number of data, and the uniqueness and the convergence of optimum values was discussed. The surface tension of molten Ag and the contact angle between Ag and graphite were measured by the use of this method. As a result, the surface tension of Ag in Ar atmosphere was γ=−1.97×10−4T+1.15 (N/m). It was found that the contact angle was 180° when the temperature attained the measuring point, and that the contact angle decreased with the holding time.
