Measurement of surface and interfacial tension using pendant drop tensiometry

A simple formula for the estimation of surface tension from two length measurements for a sessile or pendant drop

“…Evaluating γ MW we get ±6 mN/m. Our value of γ MW = 69 ± 6 mN/m is then in agreement with the value of 72 mN/m given by the authors [15]. We intend to carry out our own experiments in due course.…”

“…Following the work of Rotenberg et al [16] and Huh and Reed [17] in 1983, many papers were published that describe the evaluation of surface tension based on the comparison of an image of the entire drop profile with numerical solutions (see for example [15,18,19]). While such an approach will be more accurate for numerical evaluation, we believe that the method described here offers complementary advantages.…”

“…To test our result we have applied Equation (5) to photographs of a pendant water drop published by [15]. Values for L x and L y were obtained using ImageJ, resulting in γ MW = TPHL 1434320 1-2-2018 Initial CE:PG 69 mN/m.…”

“…This should prove to be a useful and instructive adjunct to the principal current methods. It yields an immediate value for the surface tension, by means of a simple formula, requiring 15 only two length measurements related to the drop profile. The same method can be applied to both sessile and pendant drops, and also bubbles.…”

Evolution of a Water Pendant Droplet: Effect of Temperature and Relative Humidity

“…Recently, Berry et al introduced a new parameter, namely the Worthington number Wo, in order to characterize the surface tension measurement precision [23]. First written as the ratio of the pendant drop volume to the maximum possible pendant drop volume, this dimensionless number is directly connected to the outer diameter of the syringe needle and pendant drops close to the critical detachment volume present the most accurate measurements.…”