Adhesion force characterization method of water-droplet sliding on superhydrophobic surface

The adhesion force of water-droplet sliding on superhydrophobic surface is essential for the wettability characterization. Direct measurement causes the deformation of water-droplet and other unfavorable factors to decrease the accuracy, and the published simulation method is generally used for qualitative characterization. Herein, we proposed a simulation method to characterize the adhesion force. Three types of superhydrophobic surfaces were designed and fabricated with femtosecond laser ablation and chemical fluorination. Wettability and structure were quantitatively characterized for establishing the simulation model. Wettability data were accurately acquired by analyzing the morphology characteristics of sliding water-droplet and superhydrophobic structures, and six types of adhesion forces were calculated. Sliding angle of simulation and measurement was adopted to analyze the availability of simulation method, and exhibited an unignorable difference (1.02 degrees - 1.85 degrees), which results from the simplification of structure model. The simplification decreases the super- hydrophobicity and accordingly increases the sliding angle, causing the deviation of adhesion force with its real value. Improving the accuracy of structure model can reduce the deviation. This study offers a novelty and available method to characterize the adhesion force of water-droplet sliding on superhydrophobic surface, and greatly promotes the development of superhydrophobic surfaces with controllable adhesion properties.