Non-Newtonian Slippery Liquid Infused Porous Surfaces: NN-SLIPS

当液体与固体表面接触时，其界面可被表面织构钉扎，从而引起普遍存在的接触角滞后现象。接触角滞后的存在对液体操作是一个挑战，并影响从自清洁涂层到微流体和石油回收的许多实际应用。受猪笼草猪笼草的启发，最近推出了SLIPS（Slipperous Liquid-Infused Porous Surfaces）。它们增强的液体流动性依赖于液体和固体之间存在润滑流体，减少与固体表面的接触，从而减少液体操纵所需的驱动力。除了影响静摩擦之外，润滑流体还通过附加流体层的存在和润湿脊的产生来影响液体运动，其中粘性耗散主要发生在润湿脊处。对SLIPS的兴趣日益增长，导致在食品包装和生物医学设备等领域的应用，这些领域涉及具有复杂（非牛顿）流变特性的流体。尽管如此，迄今为止，大多数SLIPS的研究主要解决简单（牛顿）液体的平衡性质或动力学。相反，预计固体结构、液体界面形状和复杂流体流变学的组合将在液体运动中起主导作用。本项目旨在探索非牛顿流体流变学对SLIPS物理学的影响。借助计算流体动力学模拟，基于最近开发的三元晶格玻尔兹曼方法，该项目将阐明SLIPS上复杂液体（流动和注入）的动力学，并在新型智能材料的设计中结合固体纹理的几何形状和复杂液体特性开发新的关键原理。

When a liquid comes into contact with a solid surface, its interface can be pinned by surface texture, giving rise to the ubiquitous phenomenon of the contact angle hysteresis. The presence of Contact Angle Hysteresis is a challenge for liquid manipulation and affects many practical applications ranging from self-cleaning coatings to microfluidics and oil recovery. Inspired by the Nepenthes pitcher plant, SLIPS (Slippery Liquid-Infused Porous Surfaces) have been recently introduced. Their enhanced liquid mobility relies on the presence of a lubricating fluid between the liquid and solid, reducing the contact to the solid surface, and therefore the driving force required for liquid manipulation. Besides impacting the static friction, lubricating fluids impact liquid motion also through the presence of an additional fluid layer and the creation of a wetting ridge, where viscous dissipation mostly takes place. The growing interest in SLIPS, lead to applications in areas such as food packaging and biomedical devices, which involve fluids with complex (non-Newtonian) rheological properties. Despite that, to date most studies of SLIPS address mainly equilibrium properties or dynamics of simple (Newtonian) liquids. In contrast, it is expected that the combination of solid texture, shape of liquid interfaces and complex fluid rheology will play a dominant role in liquid motion. This project aims at exploring the impact of non-Newtonian liquid rheology on the Physics of SLIPS. With the aid of computational fluid dynamics simulations, based on a recently developed ternary lattice Boltzmann method, this project will elucidate the dynamics of complex liquids (both flowing and infusing) on SLIPS and develop new key principles combining the geometry of solid textures and complex liquid properties in the design of new smart materials.