Effect of viscous force on dynamic contact angle measurement using Wilhelmy plate method

Assessment and Interpretation of Surface Wettability Based on Sessile Droplet Contact Angle Measurement: Challenges and Opportunities

“…Yet, the 2D analysis omits the variation in sample thickness commonly exist in anisotropic systems. Others have modified the force balance equation (Equation ) to account for the effect of viscous and head resistance forces that becomes dominant under high velocity and high viscosity testing conditions …”

Study on the enhancing water collection efficiency of cactus- and beetle-like biomimetic structure using UV-induced controllable diffusion method and 3D printing technology

“…7c , each droplet is driven by gravitational force ( G ) and resisted by viscous force ( f v ) arising from the substrate, which reads: f v = ηS (d v /d y ), where η is the coefficient of viscosity of water, d v /d y is the velocity gradient of water, and S is the contact area between droplet and substrate. 48 In the case of sample with holes, the contact area between the droplet and the substrate is smaller than that of the sample without holes, resulting in the decline of f v and speedup of droplet transportation on the substrate. Therefore, the sample with constructed parameters of mass ratio adhesives 1 : 1, cone distance 2 mm and printed holes was chosen in consideration of the optimized water-collection performance.…”

Viscous drag force model for dynamic Wilhelmy plate experiments

“…However, the drag force has been identified as a source of error in dynamic Wilhelmy plate experiments at moderate to high Ca [30]. In experiments where viscous drag forces cannot be ignored, three models have been proposed by Wang et al [30], Karim and Kavehopour [37], and Ramé [31] and are listed in Table I. These viscous drag models have been rewritten to be consistent with the coordinate system and variables shown in Fig.…”