Wetting Transition of the Ethanol鈥揥ater Droplet on Smooth and Textured Surfaces

详细信息    查看全文

• 作者：Atanu K. Metya ; Sandip Khan ; Jayant K. Singh
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：February 27, 2014
• 年：2014
• 卷：118
• 期：8
• 页码：4113-4121
• 全文大小：560K
• 年卷期：v.118,no.8(February 27, 2014)
• ISSN：1932-7455

文摘

The wetting behavior of an ethanol鈥搘ater droplet is investigated on graphitic smooth and rough surfaces using molecular dynamics simulations. On a smooth surface, ethanol molecules prefer to stay at the vapor鈥搇iquid and solid鈥搇iquid interfaces. The contact angle of a droplet on a smooth surface decreases with an increase in the ethanol concentration from 0 to 30 wt %. The corresponding line tension increases from 3 脳 10^鈥?1 to 9.4 脳 10^鈥?1 N at 300 K. The critical weight percentage for complete wetting is found to be approximately 50%. In the case of a textured graphite surface, with the addition of ethanol molecules, the Cassie鈥揃axter state of a drop is transformed into the Wenzel state via the partial Wenzel state, with ethanol molecules filling the rough region, leading to an increase in its wettability. A linear relation of 1 + cos 胃 with the roughness parameter associated with the Cassie鈥揃axter and Wenzel states is observed, indicating that the solid鈥搇iquid interfacial tension is directly proportional to the roughness parameter. This behavior is akin to that seen for the case of pure liquid. The hydrogen bonding and density profile are analyzed to understand the wetting states of the blended drop.