Atomic Force Microscope to Study Fluid Flow through Sub-Nanometer Pores

由石墨烯等二维材料制成的膜有望比传统膜的性能高几个数量级。这是由于材料的原子厚度，使其能够支持亚纳米孔径，能够过滤分子的大小，同时对流体流动施加最小的流体动力阻力。实现这些膜的有用规模将需要详细了解原子薄材料中流体通过孔隙的传输。然而，关于这种流动的实验信息仍然很少，并且已经发表的少数实验研究报告了尚未得到很好理解的非常有趣的输运现象。******我请求资金购买原子力显微镜（AFM）来执行各种类型的传输通过单个亚纳米孔在原子薄膜的第一次测量。我将进行第一批研究，测量成像孔隙结构的渗透率，液体通过石墨烯孔隙的传输，通过表面吸附和扩散增强气体渗透率，以及石墨烯以外二维材料中孔隙的渗透率。******原子力显微镜是唯一被证明能够测量通过这些系统的微小流速的工具。然而，开发观察这些流速和测量样品的技术所需的时间阻碍了共用设备的使用。此外，我将在2019年1月开始一个新的实验室，这个设备将加速我的研究计划，让我在第一年开始实验，同时我建立了追求其他研究目标所需的设备和能力。******该设备对于训练学生进行实验亚纳米尺度流体力学的研究至关重要，这将使他们对纳米流体学这个有趣但相对未开发的领域做出重大贡献。它将为他们提供一套不同寻常的技能，使他们能够开展独立的研究事业，并获得半导体和材料行业所重视的计量专业知识。******该设备的研究将使我们能够解决二维材料中亚纳米孔的传输中未解决的问题，并发现未知的流体流动现象，因为边界的原子细节变得重要。它将促进我们对最小长度尺度的质量传输的理解，并支持研究开发具有更高渗透性的膜，用于清洁水和能源

Membranes made from two-dimensional materials such as graphene promise orders of magnitude higher performance than conventional membranes. This is made possible by the atomic thinness of the material, allowing it to support sub-nanometer pores capable of filtering molecules by size while imposing minimal hydrodynamic resistance to fluid flow. Realizing these membranes on a useful scale will require a detailed understanding of fluid transport across pores in atomically thin materials. However, there remains very little experimental information about such flows and the few experimental studies that have been published report very interesting transport phenomena that are not well understood. ******I request funds to purchase an atomic force microscope (AFM) to perform the first measurements of various types of transport through single sub-nanometer pores in atomically thin membranes. I will conduct the first studies measuring the permeance of imaged pore structures, liquid transport across graphene pores, gas permeance enhancement by surface adsorption and diffusion, and the permeance of pores in two-dimensional materials beyond graphene.******Atomic force microscopy is the only tool proven capable of measuring the minuscule flow rates through these systems. However, the time required to develop techniques to observe these flow rates and to measure samples precludes the use of shared equipment. Furthermore, I am starting a new lab in January 2019 and this equipment will accelerate my research program by allowing me to begin experiments within the first year, while I build up the equipment and capabilities needed to pursue my other research objectives. ******This equipment is essential to training students to conduct research in experimental sub-nanometer scale fluid mechanics, which will position them to make significant contributions to the interesting but relatively unexplored field of nanofluidics. It will give them an uncommon skillset with which to launch independent research careers and metrology expertise valued in the semiconductor and materials industries.******The research enabled by this equipment will allow us to resolve unanswered questions in transport across sub-nanometer pores in two-dimensional materials and discover yet unknown fluid flow phenomena as the atomic details of boundaries become important. It will advance our understanding of mass transport at the smallest length scale and support research to develop membranes with orders of magnitude higher permeance for applications in clean water and energy.**