State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
ACS Appl Mater Interfaces. 2012 May;4(5):2775-80. doi: 10.1021/am300423p. Epub 2012 Apr 30.
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 SiO(2) microspheres deposition is achieved. What's 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.
已经证明了一种简单而新颖的方法，可以在液滴蒸发过程中通过添加水溶性聚合物添加剂来避免咖啡环结构。聚合物添加剂导致接触线（CL）的运动，这是由粘度和马兰戈尼效应引起的。粘度对径向向外流动提供了很大的阻力。这导致少量球体沉积在液滴边缘，这不利于 CL 的固定。液滴蒸发过程中液滴边缘处聚合物浓度的变化导致马兰戈尼效应有助于 CL 的运动。因此，可以实现均匀和有序的宏观 SiO(2) 微球沉积。更重要的是，不同的水溶性聚合物可以消除咖啡环效应。这种方法将适用于广泛的水体系，并将对液滴沉积在生化分析和材料沉积中的广泛应用具有重要意义。
