Suppression of the Coffee Ring Effect by Hydrosoluble Polymer Additives

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• 作者：Liying Cui ; Junhu Zhang ; Xuemin Zhang ; Long Huang ; Zhanhua Wang ; Yunfeng Li ; Hainan Gao ; Shoujun Zhu ; Tieqiang Wang ; Bai Yang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2012
• 出版时间：May 23, 2012
• 年：2012
• 卷：4
• 期：5
• 页码：2775-2780
• 全文大小：271K
• 年卷期：v.4,no.5(May 23, 2012)
• ISSN：1944-8252

文摘

A simple and novel method has been demonstrated for avoiding coffee ring structure based on hydrosoluble polymer additives during droplet evaporation. The polymer additives lead to the motion of the contact line (CL) resulted from the viscosity and Marangoni effect. The viscosity provides a large resistance to the radially outward flow. It results in a small amount of spheres deposited at droplet edge, which do not facilitate the pinning of the CL. The Marangoni effect resulted from the variation of polymer concentration at droplet edge during droplet evaporation contributes to the motion of the CL. Thus, uniform and ordered macroscale SiO₂ microspheres deposition is achieved. What鈥檚 more, the coffee ring effect can be eliminated by different hydrosoluble polymer. This method will be applicable to a wide of aqueous system and will be of great significance for extensive applications of droplet deposition in biochemical assays and material deposition.

Keywords:

coffee ring; hydrosoluble polymer additives; dewetting; droplet deposition; the motion of contact line