Multiphase Multicomponent Lattice Boltzmann Method for Modelling Wetting on Liquid Infused Surfaces

液体注入表面(LIS)是一种受大自然(猪笼草)启发的新型表面，可以排斥任何类型的液体。LI是通过在粗糙、多孔或有纹理的表面浸渍润湿润滑剂来构建的，从而赋予它们良好的表面性能，包括自清洁、防污垢和增强热传递。这些功能表面有可能解决广泛的社会、环境和工业挑战。例子包括家庭食物垃圾，其中超过20%是由包装和残留物造成的；减轻热交换器污垢，据估计占全球二氧化碳排放量的2.5%。尽管LIS涂料具有巨大的潜力，但到目前为止，由于缺乏坚固性和耐久性，LIS涂料在实践中尚不适用于绝大多数应用。在根本层面上，润滑剂的存在导致了一类新颖但鲜为人知的润湿现象，这是由于薄膜润滑膜动力学和宏观液滴动力学之间的丰富相互作用，例如液滴之间的有效远程相互作用和延迟合并。这也导致了LIS特有的许多开放的挑战，例如由于润滑油耗尽而导致的性能下降。EPSRC联谊会项目的积分是一种基于格子Boltzmann方法(LBM)的创新的数值方法来求解流体的运动方程。LBM的一个主要优点是，可以将关键的粗粒度分子信息结合到界面现象的描述中，同时保持计算上的易用性，以研究与LIS相关的宏观流动动力学。LBM还非常灵活，可以应对界面形状和拓扑的变化，以及复杂的曲面几何，并且非常适合高性能计算。开发的模拟框架将是第一个完全解决LIS上润湿动力学复杂性的框架，代码将通过OpenLB开放源代码。利用LBM模拟并得到来自四个项目合作伙伴的实验数据的支持，我将在我们对LIS的理解方面提供亟需的步骤改变。预期结果包括：(I)最大限度地减少润滑剂消耗的设计标准，这被认为是LIS的主要弱点；(Ii)在各种润滑剂可用性和润湿性条件下，对LIS上液滴和润滑剂半月面动力学的新见解；以及(Iii)润滑油对LIS上液滴相互作用的定量模型。大多数LIS应用程序(如果不是全部的话)都面临这些关键挑战。解决这些问题是更好地设计LIS设计的唯一途径。最后，将利用项目中开发的计算工具和基本见解来探索基于LIS的两项潜在颠覆性技术，这两项技术与可持续发展中的能源-水-环境关系高度相关。首先，我将与埃克森美孚合作，研究在碳捕获方面的应用，探索如何将液体固定在具有大表面积与体积比的LIS中。更具体地说，基于液态胺的二氧化碳捕获是一种重要的商业实践方法，但昂贵的基础设施和操作阻碍了其广泛实施。令人兴奋的是，LIS可能会为使用液态胺的更经济的碳捕获方法提供一种解决方案。其次，受当前全球水供需缺口47%以及减少表面活性剂使用的环境压力的推动，我将与宝洁公司合作研究清洁的新方法。关键的想法是使用配方液体的薄膜来诱导固体表面上不需要的液滴去湿，从而在更局部地引入润湿性改变，并使用大量减少的资源。

Liquid infused surfaces (LIS) are a novel class of surfaces inspired by nature (pitcher plants) that repel any kind of liquid. LIS are constructed by impregnating rough, porous or textured surfaces with wetting lubricants, thereby conferring them advantageous surface properties including self-cleaning, anti-fouling, and enhanced heat transfer. These functional surfaces have the potential to solve a wide range of societal, environmental and industrial challenges. Examples range from household food waste, where more than 20% is due to packaging and residues; to mitigating heat exchanger fouling, estimated to be responsible for 2.5% of worldwide CO2 emissions.Despite their significant potential, however, to date LIS coatings are not yet viable in practice for the vast majority of applications due to their lack of robustness and durability. At a fundamental level, the presence of the lubricant gives rise to a novel but poorly understood class of wetting phenomena due to the rich interplay between the thin lubricant film dynamics and the macroscopic drop dynamics, such as an effective long-range interaction between droplets and delayed coalescence. It also leads to numerous open challenges unique to LIS, such as performance degradation due to lubricant depletion.Integral to this EPSRC Fellowship project is an innovative numerical approach based on the Lattice Boltzmann method (LBM) to solve the equations of motion for the fluids. A key advantage of LBM is that key coarse-grained molecular information can be incorporated into the description of interfacial phenomena, while remaining computationally tractable to study the macroscopic flow dynamics relevant for LIS. LBM is also highly flexible to account for changes in the interface shape and topology, complex surface geometry, and it is well-suited for high performance computing. The developed simulation framework will be the first that can fully address the complexity of wetting dynamics on LIS, and the code will be made available open source through OpenLB. Harnessing the LBM simulations and supported by experimental data from four project partners, I will provide the much-needed step change in our understanding of LIS. The expected outcomes include: (i) design criteria that minimise lubricant depletion, considered the main weakness of LIS; (ii) new insights into droplet and lubricant meniscus dynamics on LIS across a wide range of lubricant availability and wettability conditions; and (iii) quantitative models for droplet interactions on LIS mediated by the lubricant. These key challenges are shared by the majority, if not all, of LIS applications. Addressing them is the only way forward to better engineer the design of LIS.Finally, the computational tools and fundamental insights developed in the project will be exploited to explore two potentially disruptive technologies based on LIS, which are highly relevant for the energy-water-environment nexus in sustainable development. First, I will investigate application in carbon capture, exploiting how liquids can be immobilised in LIS with a large surface to volume ratio, in collaboration with ExxonMobil. More specifically, liquid amine-based CO2 capture is an important and commercially practised method, but the costly infrastructure and operation prohibit its widespread implementation. Excitingly, LIS may provide a solution to a more economical carbon capture method using liquid amine. Second, motivated by the current gap of 47% in global water supply and demand, as well as environmental pressure to reduce the use of surfactants, I will examine new approaches to clean in collaboration with Procter & Gamble. The key idea is to induce dewetting of unwanted liquid droplets on solid surfaces using a thin film of formulation liquid, thus introducing wettability alteration more locally and using much reduced resources.