Simulação do comportamento superhidrofóbico em rampas de pilares

Abstract

We present a two-dimensional simulation based on the cellular Potts model (CPM) of the properties of smooth and pillar structured hydrophobic surfaces. For a surface having superhidrophobic behavior, a drop of water deposited on it should have: (I) high-value of contact angle ( ), (II) low hysteresis ( <10°) and (III) high sliding speed. Using a smooth surface with hydrophobic character we modify its structure for the purpose to obtain a surface with superhydrophobic character. On this structured surface with pillars we varied the distance (b) and the height of the pillars (h) to analyze how these parameters can influence the superhydrophobic phenomenon. We also analyzed how the parameter (related to the inverse of the compressibility of the liquid), the parameter fluctuation (T) and gravity interfere in the system. We observed that the contact fraction (f) between the liquid and the solid has strong influence on superhydrophobicity as mentioned in items I, II and III above. This study was able to determine a region of values f, where superhydrophobic behavior is intensified, i.e, I, II and III are satisfied. In the study of state transition we analyze how the variation of the model parameters influence the passage from Cassie to Wenzel states. The results obtained in our simulations are consistent with experimental results found in literature.