Controlling coffee ring structure on hydrophobic polymer surface by manipulating wettability with O₂ plasma

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• 作者：Li-Ying Cui^a ; ^b ; Yu Yan^b ; Xin-Yu Zhao^a ; Cun-Long Yu^a ; Ying Ma^c ; Bai Yang^b ; ^{byangchem@jlu.edu.cn}
• 关键词：Coffee ring ; SiO2 microspheres deposition ; Drop evaporation ; O2 plasma ; PS surface
• 刊名：Chinese Chemical Letters
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：28
• 期：1
• 页码：1-5
• 全文大小：723 K
• 卷排序：28

文摘

A simple and novel method is firstly reported for controlling coffee ring structure on polystyrene (PS) film surface by O2 plasma. O2 plasma treatment leads to the wettability change of PS surface from hydrophobic to hydrophilic. For hydrophilic PS surface the coffee ring structure is avoided relying on the motion of contact line (CL) while SiO2 microspheres are left. The motion of the CL is produced based on the viscosity and Marangoni effect with the addition of polymer additives. For hydrophobic PS surface coffee ring structure still persists even with polymer additives because SiO2 microspheres transfer with the motion of the CL at the beginning of droplet evaporation and accumulate at the droplet edge at late stage with the pinning of the CL. As a result, uniform and macroscale SiO2 microspheres deposition without coffee ring structure and SiO2 microspheres deposition with coffee ring structure are controlled by O2 plasma. This method provides a new way to tune coffee ring structure with smart surface and may be potentially useful for a range of application at material deposition and diagnosing diseases.