Mensink Liz I S, Snoeijer Jacco H, de Beer Sissi
Physics of Fluids, MESA+ Institute for Nanotechnology, and Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Macromolecules. 2019 Mar 12;52(5):2015-2020. doi: 10.1021/acs.macromol.8b02409. Epub 2019 Feb 20.
End-anchoring polymers to a solid surface to form so-called polymer brushes is a versatile method to prepare robust functional coatings. We show, using molecular dynamics simulations, that these coatings display rich wetting behavior. Depending on the interaction between the brushes and the polymeric droplets as well as on the self-affinity of the brush, we can distinguish between three wetting states: mixing, complete wetting, and partial wetting. We find that transitions between these states are largely captured by enthalpic arguments, while deviations to these can be attributed to the negative excess interfacial entropy for the brush droplet system. Interestingly, we observe that the contact angle strongly increases when the softness of the brush is increased, which is opposite to the case of drops on soft elastomers. Hence, the Young to Neumann transition owing to softness is not universal but depends on the nature of the substrate.
将聚合物末端锚定在固体表面以形成所谓的聚合物刷是制备坚固功能涂层的通用方法。我们通过分子动力学模拟表明，这些涂层表现出丰富的润湿行为。根据刷与聚合物液滴之间的相互作用以及刷的自亲和性，我们可以区分三种润湿状态：混合、完全润湿和部分润湿。我们发现这些状态之间的转变在很大程度上由焓的因素决定，而与这些情况的偏差可归因于刷 - 液滴系统的负过量界面熵。有趣的是，我们观察到当刷的柔软度增加时，接触角会大幅增加，这与软弹性体上液滴的情况相反。因此，由于柔软度导致的杨氏到诺伊曼转变并非普遍适用，而是取决于基底的性质。
