Liquid films with high surface modulus moving in tubes: dynamic wetting film and jumpy motion

Partial wetting of thin solid sheets under tension

We consider the equilibrium of liquid droplets sitting on thin elastic sheets that are subject to a boundary tension and/or are clamped at their edge. We use scaling arguments, together with a detailed analysis based on the Föppl-von-Kármán equations, to show that the presence of the droplet may significantly alter the stress locally if the tension in the dry sheet is weak compared to an intrinsic elasto-capillary tension scale $γ^{2/3}(Et)^{1/3}$ (with $γ$ the droplet surface tension, $t$ the sheet thickness and $E$ its Young modulus). Our detailed analysis suggests that some recent experimen…

Static wetting on deformable substrates, from liquids to soft solids

Young's law fails on soft solid and liquid substrates where there are substantial deformations near the contact line. On liquid substrates, this is captured by Neumann's classic analysis, which provides a geometrical construction for minimising the interfacial free energy. On soft solids, the total free energy includes an additional contribution from elasticity. A linear-elastic model incorporating an out-of-plane restoring force due to solid surface tension was recently shown to accurately predict the equilibrium shape of a thin elastic film due to a large sessile droplet. Here, we extend thi…

软梯度表面上液滴的自发运动

Spontaneous Motion of Liquid Droplets on Soft Gradient Surfaces

本研究探讨了液滴在交联梯度软凝胶上的自发运动，发现其由表面能差异驱动，可克服重力爬坡，为软耗散界面液滴控制提供新方法。

从三流体交界到杨氏定律：本构与刚性支撑极限下的润湿

From a three-fluid junction to Young's law: Constitutive and rigid-support limits of wetting

通过有序连续介质构造，将刚性固体上的杨氏定律与三流体交界处的纽曼平衡联系起来，阐明刚性支撑极限下润湿的力学机制，并给出收敛性结果。

Statics of polymer droplets on deformable surfaces

The equilibrium properties of polymer droplets on a soft deformable surface are investigated by molecular dynamics simulations of a bead-spring model. The surface consists of a polymer brush with irreversibly end-tethered linear homopolymer chains onto a flat solid substrate. We tune the softness of the surface by varying the grafting density. Droplets are comprised of bead-spring polymers of various chain lengths. First, both systems, brush and polymer liquid, are studied independently in order to determine their static and dynamic properties. In particular, using a numerical implementation o…

A liquid contact line receding on a soft gel surface : dip-coating geometry investigation

We studied the dynamics of a liquid contact line receding on a hydrophobic soft gel (SBS-paraffin). In order to realize a well-defined geometry with an accurate control of velocity, a dip-coating setup was implemented. Provided that the elastic modulus is small enough, a significant deformation takes place near the contact line, which in turn drastically influences the wetting behaviour. Depending on the translation velocity of the substrate, the contact line exhibits different regimes of motions. Continuous motions are observed at high and low velocities, meanwhile two types of stick-slip mot…