National Engineering Laboratory for Pipeline Safety, Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum, Beijing, 18# Fuxue Road, Changping District, 102249 Beijing, China.
Soft Matter. 2018 Sep 26;14(37):7605-7614. doi: 10.1039/c8sm00884a.
The dynamic of contact formation between soft materials immersed in a fluid is accompanied by fluid drainage and elastic deformation. As a result, controlling the coupling between lubrication pressure and elasticity provides strategies to design materials with reversible and dynamic adhesion to wet or flooded surfaces. We characterize the elastic deformation of a soft coating with nanometer-scale roughness as it approaches and contacts a rigid surface in a fluid environment. The lubrication pressure during the approach causes elastic deformation and prevents contact formation. We observe deformation profiles that are drastically different from those observed for elastic half-space when the thickness of the soft coating is comparable to the hydrodynamic radius. In contrast, we show that surface roughness favors fluid drainage without altering the elastic deformation. As a result, the coupling between elasticity and slip (caused by surface roughness) can lead to trapped fluid pockets in the contact region.
当软材料浸入流体中时，接触形成的动态伴随着流体的排出和弹性变形。因此，控制润滑压力和弹性之间的耦合为设计具有可逆和动态湿附着或淹没表面附着力的材料提供了策略。我们描述了软涂层在纳米级粗糙度下在流体环境中接近和接触刚性表面时的弹性变形。在接近过程中，润滑压力会导致弹性变形并防止接触形成。我们观察到的变形轮廓与弹性半空间观察到的轮廓有很大的不同，当软涂层的厚度与流体动力半径相当时。相比之下，我们表明表面粗糙度有利于排水而不改变弹性变形。因此，弹性和滑动（由表面粗糙度引起）之间的耦合会导致在接触区域产生被困的流体口袋。
