中国物理B ›› 2013, Vol. 22 ›› Issue (10): 106801-106801.doi: 10.1088/1674-1056/22/10/106801
• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇 下一篇
刘思思, 张朝辉, 张寒冰, 周杰, 何建国, 尹恒洋
Liu Si-Si (刘思思), Zhang Chao-Hui (张朝辉), Zhang Han-Bing (张寒冰), Zhou Jie (周杰), He Jian-Guo (何建国), Yin Heng-Yang (尹恒洋)
摘要: Textured silicon (Si) substrates decorated with regular microscale square pillar arrays of nearly the same side length, height, but different intervals are fabricated by inductively coupled plasma, and then silanized by self-assembly octadecyltrichlorosilane (OTS) film. The systematic water contact angle (CA) measurements and micro/nanoscale hierarchical rough structure models are used to analyze the wetting behaviors of original and silanized textured Si substrates each as a function of pillar interval-to-width ratio. On the original textured Si substrate with hydrophilic pillars, the water droplet possesses a larger apparent CAs (>90°) and contact angle hysteresis (CAH), induced by the hierarchical roughness of microscale pillar arrays and nanoscale pit-like roughness. However, the silanized textured substrate shows superhydrophobicity induced by the low free energy OTS overcoat and the hierarchical roughness of microscale pillar arrays, and nanoscale island-like roughness. The largest apparent CA on the superhydrophobic surface is 169.8°. In addition, the wetting transition of a gently deposited water droplet is observed on the original textured substrate with pillar interval-to-width ratio increasing. Furthermore, the wetting state transition is analyzed by thermodynamic approach with the consideration of the CAH effect. The results indicate that the wetting state changed from a Cassie state to a pseudo-Wenzel during the transition.
中图分类号: (Wetting)