Interfacial control of transport applications

这个发现项目旨在为三种传输应用创造一类新的界面操作：蒸发、（滑）电渗透和电渗析。这些过程是无所不在和根本的，影响着水和可持续能源技术的应用。******关于热传递，第一个项目旨在通过改变基材的润湿性和（热）导电性来控制干燥液滴中的颗粒排列。系统的实验测量温度分布和三维流场引起的蒸发在一个表面上的固体干燥液滴将进行。这一目前缺乏的关键数据，将有助于利用简单而强大的蒸发方法，对表面上的物质进行分类和排列的最佳设计。******为了增强动量和电荷输运，在第二个项目中，将设计和生成一种新型的改性超疏水表面，以减少微流体中的阻力，这是一个长期存在的挑战。将制造具有纵向微槽的疏水微通道，以在微观结构上捕获气相流体，从而产生无剪切界面，从而减少壁面摩擦。探索流场的高分辨率；实验研究了气液界面几何形状对微流体滑移的影响。在类似的物理机制下，期望在带电气液界面上增强电荷/离子输运。然而，没有这样的实验验证存在。因此，我将通过修改超疏水通道，使其与电极具有电荷选择性，来研究相关的电学和流体动力学效应。******利用离子传输，各种水和能源技术使用电荷选择表面或膜进行操作。例如，电渗析是一种广泛用于海水淡化和水净化的方法。在电渗析中，离子在电强迫下在电荷选择表面附近形成浓度梯度，这反过来限制了离子的传输。第三个项目通过实验检查由离子浓度梯度触发的流体动力学过程，解决了电渗析的这一限制步骤。将进行高分辨率的电、离子浓度和流场测量，以了解它们对高效电渗析性能的复杂相互作用。**

This Discovery program is directed towards creating a new class of interfacial manipulation for three transport applications: evaporation, (slippery) electro-osmosis, and electrodialysis. These processes are omnipresent and fundamental, influencing applications in technology of water and sustainable energy. ******Concerning heat transport, the first project aims at controlling particle arrangement in a drying droplet by varying substrate properties of wetting and (thermal) conductivity. Systematic experimental measurements of temperature profiles and 3D flow fields induced by evaporation in a sessile drying droplet on a surface will be carried out. This crucial data, which is currently lacking, would shed light on optimal design for sorting and arranging materials on surfaces, using the simple and powerful method of evaporation.******To enhance momentum and charge transport, in the second project, a new type of modified superhydrophobic surfaces will be designed and generated for drag reduction in microfluidics, which is a long-standing challenge. Hydrophobic micro-channels with longitudinal microgrooves will be fabricated to entrap gas phase fluid-creating shear-free interfaces-upon the microstructures, resulting in the reduction of wall-friction. The high-resolution of flow field will be probed; the effect of geometry of gas-liquid interfaces on microfluidic slippage will be experimentally investigated. Under a similar physical mechanism, enhancement of charge/ion transport on charged gas-liquid interface is expected. However, no such experimental verification exists. I will hence examine the associated electrical and fluid dynamical effects by modifying the superhydrophobic channels to be charge-selective with electrodes.******Employing ion transport, various water and energy technologies are operated using charge selective surfaces or membranes. For instance, electrodialysis is a widely used method for desalination and water purification. In electrodialysis, ions develop concentration gradients adjacent to a charge selective surface under an electrical forcing, which in turn limits the ion transport. The third project tackles this limiting step of electrodialysis, by experimentally examining the hydrodynamic processes triggered by the gradient of ion concentrations. High-resolution measurements of electrical, ion concentration and flow fields will be conducted to understand their complex interplay for efficient electrodialysis performance. **