表面微观结构对液滴浸润的影响特性

he pillar-structured hydrophobic surfaces were prepared with the polydimethyl-siloxane (PDMS) substrate using photolithography techniques. The wettability of the hydrophobic surfaces with different microstructure spacing and height were studied. Experimental results show that the contact angle will increase when the microstructure spacing increase. Howerer, the roughness decrease when the microstructure spacing increases and the contact angle on smooth surfaces is small. So there must be existing a critical microstructure spacing at which the contact angle on the hydrophobic surface achieves the biggest value. Furtherfore, the contact angle on the hydrophobic surfaces with different micropillar height. The results showed that the micropillar height has little influence on initial wetting characteristics but has great influence on the stability of wetting status. The micropillar height greater, the wetting status of the droplet is more steady. When the microstructure height is small, the wetting statues are not steady. Therefore, a critical micropillar height must be existed. The wetting status are steady when the micropillar heights are higher than the critical height and the droplets will suddenly collapse when the micropillat heights are small than the critical height. .