Abstract: Wetting properties are significant for a hydrophobic surface and normally characterized by the equilibrium contact angle. In this manuscript, a mesoscopic method based on multiphase multiple-relaxation-time Lattice Boltzmann method has been presented and applied to simulate the contact angle at three-phase interfaces of a solid surface with micro-pillar structure. The influence of different parameters including pillar height, pillar width, inter-pillar spacing, intrinsic contact angle and the volume of the liquid drop on the equilibrium contact angle has been comprehensively investigated. The effect of geometry parameters of the micro-pillar structure on the wetting transition from Cassie–Baxter state to Wenzel state has also been studied. The results indicate that when the inter-pillar spacing is less than a certain value or the pillar height is greater than a certain value, the contact form between the droplet and the surface satisfies the Cassie–Baxter state. When the contact form satisfies the Cassie–Baxter state, the contact angle gradually increases with the increase of the inter-pillar spacing; the contact angle does not change significantly with the pillar height; the contact angle gradually decreases and approaches the intrinsic contact angle with the pillar width increases. Moreover, the contact angle increases with the increase of the intrinsic contact angle, and the contact angle is not sensitive to the change of droplet volume when the droplet volume is between 0.5 and10 μl.

Key words: Bioinspired hydrophobic surface , · Wettability , · Cassie–Baxter state , · Wenzel state , · Lattice Boltzmann method , · Mesoscale simulation