Elucidating Hydrodynamics at Confined Interfaces for Artificial Active Fluidics and Beyond

构成我们身体的活细胞的表面由尺寸不到一纳米(即人类头发直径的万分之一)的精心设计的微小毛孔组成。自然界已经进化出这些孔来有效地利用分子间作用力和表面效应，以实现非凡的水/离子选择性和离子传输，甚至与浓度梯度相反。因此，它们在人类肾脏清除血液中的废物/额外液体的功能中发挥着关键作用，并允许脑细胞(即神经元)产生大脑感知和计算所需的电脉冲。例如，通过神经元细胞膜的浓度梯度驱动离子传输产生电信号，并以每秒数十米的速度传输它们作为一种通信手段。这项拟议的研究旨在在实验室内制造类似的孔，以制造(I)人造流体设备，允许以其语言直接与细胞通信(交换离子/水分子)，以及(Ii)通过混合淡水和海水来产生能量的膜，以及以最小的二氧化碳产量能源高效地去除海水中的盐。与花园软管中的水流动不同，人们几乎不了解通过纳米大小的孔的流体运动的物理原理。此外，机械制造的小孔仍然难以分离出大小和性质相似的离子(如钠和钾)。因此，在液体在固体表面的摩擦、强化分子分离的机制、受限几何空间中的离子传输及其控制等基本问题上仍有许多需要理解的地方。这项拟议的研究旨在全面了解离子/水分子在极端限制条件下如何与机械制造的微小孔壁相互作用。这将通过研究从这种微小的孔中涌出的微观流动(根据流量/离子通量)来实现，同时调节孔壁的电导率和电荷。这些研究将为液体在固体表面的摩擦提供定量的系统认识，为选择合适的通道壁材提供参考，以精确控制受限几何形状的流体传输，实现更高的水/离子选择性，如生物孔。在整个奖学金项目中，我还将在基础/设备层面发展基本的理论理解和高级建模，以推进设备原型的实验和优化。在这些发现的基础上，该奖学金将建立(I)用于离子传输的人工流体设备和基于生物电子接口和存储设备的制造，以及(Ii)用于水净化和从盐浓度梯度中收集能量的膜。从该奖学金的第四年开始，我将与曼彻斯特的石墨烯工程创新中心合作，扩大用于能源和环境应用的流体设备和膜制造的规模，以期为英国的能源独立做出贡献，并在2050年实现温室气体净零排放。此外，我和我的团队将开发用于实验确定受限几何图形中的分子排列的方案，以使其对受限流体传输的贡献合理化。因此，该奖学金全面解决了当今纳米流体学研究中的知识空白，并为在受限流体传输、表面科学和固体物理的界面上建立新的研究方向铺平了道路。所有这一切，除了制作有影响力的出版物和专利外，还使我能够成长为该领域的领导者，朝着我在英国建立受自然启发的纳米流体研究中心的长期目标前进，以应对世界各地的一系列重大挑战(清洁增长；可持续发展；食品用水和能源)。

The surfaces of the living cells that make up our bodies consist of exquisitely engineered tiny pores of size less than a nanometer (i.e., one ten-thousandth of the diameter of a human hair). Nature has evolved these pores to efficiently harness inter-molecular forces and surface effects for achieving exceptional water/ion selectivity and ion transport even counter to concentration gradients. Therefore, they play a critical role in functioning of human kidneys to remove waste/extra-fluids from the blood and, allow brain-cells (i.e., neurons) to generate electrical pulses required for the brain to sense and compute. For example, concentration gradients driven ion transport across a neuron cell membrane generates electrical signals and transmit them with speeds of tens of meters per second as a means of communication. The proposed research aims at making similar pores inside a laboratory to make (i) artificial fluidic devices that allow direct communication to/from cells in their language (exchanging ions/water molecules), and (ii) membranes for producing energy by mixing fresh water with seawater and energy efficient removal of salt from seawater with minimal production of carbon dioxide.Unlike water flow in a garden hose, the physics of fluidic motion through the pores of nanometer-size is barely understood. Also, machine-made pores still struggle to separate ions (like sodium and potassium) with similar size and properties. Therefore, there remains much to be understood on fundamental issues such as friction of liquids on solid surfaces, mechanisms for enhanced molecular separation, and ionic transport in confined geometries and its control. The proposed research aims at establishing a comprehensive understanding of how ions/water molecules interact with the walls of machine-made tiny pores under extreme confinements. This will be achieved through investigation of microscopic flows (in terms of flow rate/ionic flux) emerging out of such tiny pores while tuning electric conductivity and electric charge of the walls of the pore. These studies will provide a systematic realization of friction for liquids on solid surfaces with quantification, which acts as reference for choosing appropriate channel wall materials for precisely controlling the fluidic transport at confined geometries to achieve enhanced water/ion selectivity like biological pores. Throughout this Fellowship, I will also develop essential theoretical understanding and advanced modelling at fundamental/device level for advancing the experiments and optimization of device-prototyping.Building on these findings, this fellowship will establish the fabrication of (i) artificial fluidic devices for ion-transport based bioelectronic interfaces and memory devices and (ii) membranes for water purification and energy harvesting from salt-concentration gradients. From the fourth year of this Fellowship, I will work with Graphene Engineering Innovation Centre at Manchester to scale up fluidic devices and membrane fabrication for energy and environmental applications with an aim of contributing to the UK's Energy Independence and achieving net zero greenhouse gases emission by 2050.Further to this Fellowship, my team and I will develop schemes for the experimental determination of the molecular arrangement in confined geometries to rationalize its contribution on confined fluidic transport. Therefore, this Fellowship comprehensively addresses knowledge gaps in present-day nanofluidics research and paves path to establish a new direction of research at the interface of confined fluidic transport, surface science and solid-state physics. All this, besides producing high-impact publications and patents, enables me to grow as a leader in this field to progress towards my long-term aim of establishing Nature-Inspired Nanofluidics Research Center in the UK to address a number of Grand Challenges (clean growth; sustainability; water and energy for food) across the world.