Illinois Institute of Technology, Dept. of Chemical and Biological Engineering, Chicago, IL 60616, United States.
Adv Colloid Interface Sci. 2015 Aug;222:517-29. doi: 10.1016/j.cis.2014.03.006. Epub 2014 Mar 16.
An aqueous solution of trisiloxane-ethoxylate surfactants (superspreaders) has fascinating surface properties that promote rapid spreading over a large area of difficult-to-wet substrates. The overall spread area achieved by an aqueous droplet containing superspreaders can be as much as 50 times greater than water, and 25 times more effective than a conventional surfactant on a leaf's surface. The phenomenon that drives superspreading is still not well understood and it is under continuous discussion.
The goal of this paper is to review the data published to elucidate the concepts and mechanisms presented in the literature and to propose a model for superspreading.
A simple model was proposed concerning the surface tension gradient (or Marangoni flow) over the curved droplet surface when the value of the wetting angle was considered. The model predicted the optimum rate of spreading vs. angle at θ = 60° and was in a satisfactory agreement with the experimental observations.
三硅氧烷乙氧基化物表面活性剂（超润剂）的水溶液具有迷人的表面特性，能促进其在难以润湿的基底上快速大面积铺展。含有超润剂的水滴滴在表面上时，其铺展面积可达水的 50 倍，在叶片表面的润湿效果比传统表面活性剂高 25 倍。但超润剂的驱动机制仍未被很好地理解，目前仍在不断讨论中。
本文的目的是回顾已发表的数据，以阐明文献中提出的概念和机制，并提出一个超润剂模型。
当考虑润湿角的值时，提出了一个关于弯曲液滴表面表面张力梯度（或马兰戈尼流）的简单模型。该模型预测了在θ=60°时最佳的铺展速率与角度，与实验观察结果相符。
