Hack Michiel A, Kwieciński Wojciech, Ramírez-Soto Olinka, Segers Tim, Karpitschka Stefan, Kooij E Stefan, Snoeijer Jacco H
Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Physics of Interfaces and Nanomaterials Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Langmuir. 2021 Mar 30;37(12):3605-3611. doi: 10.1021/acs.langmuir.0c03571. Epub 2021 Mar 18.
The wetting properties of multicomponent liquids are crucial to numerous industrial applications. The mechanisms that determine the contact angles for such liquids remain poorly understood, with many intricacies arising due to complex physical phenomena, for example, due to the presence of surfactants. Here, we consider two-component drops that consist of mixtures of vicinal alkanediols and water. These diols behave surfactant-like in water. However, the contact angles of such mixtures on solid substrates are surprisingly large. We experimentally reveal that the contact angle is determined by two separate mechanisms of completely different nature, namely, Marangoni contraction (hydrodynamic) and autophobing (molecular). The competition between these effects can even inhibit Marangoni contraction, highlighting the importance of molecular structures in physico-chemical hydrodynamics.
多组分液体的润湿性对众多工业应用至关重要。决定此类液体接触角的机制仍鲜为人知，由于复杂的物理现象，例如表面活性剂的存在，会产生许多复杂情况。在此，我们考虑由邻位链烷二醇和水的混合物组成的两组分液滴。这些二醇在水中表现出类似表面活性剂的性质。然而，此类混合物在固体基质上的接触角却出奇地大。我们通过实验揭示，接触角由两种性质完全不同的独立机制决定，即马兰戈尼收缩（流体动力学）和自憎（分子层面）。这些效应之间的竞争甚至会抑制马兰戈尼收缩，凸显了分子结构在物理化学流体动力学中的重要性。
