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出几个数量级。这是通过材料的原子薄度实现的，使其能够支持能够按大小过滤分子的亚纳米孔，同时对流体流动施加最小的流体动力学阻力。实现这些膜在一个有用的规模将需要一个详细的了解，在原子级薄的材料中的孔隙流体传输。然而，关于这种流动的实验信息仍然很少，已经发表的少数实验研究报告了非常有趣的传输现象，这些现象还没有得到很好的理解。** 我申请资金购买原子力显微镜（AFM），以执行通过原子薄膜中单个亚纳米孔的各种类型的传输的第一次测量。我将进行第一项研究，测量成像孔隙结构的渗透性，石墨烯孔隙中的液体传输，通过表面吸附和扩散增强气体渗透性，以及石墨烯以外二维材料中孔隙的渗透性。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量的工具。但是，由于需要时间来开发观察这些流速和测量样品的技术，因此无法使用共用设备。此外，我将在2019年1月开始一个新的实验室，这台设备将加快我的研究计划，让我在第一年内开始实验，同时我建立了追求其他研究目标所需的设备和能力。** 该设备对于培养学生进行实验亚纳米尺度流体力学研究至关重要，这将使他们能够为有趣但相对未开发的纳米流体领域做出重大贡献。它将为他们提供一套不寻常的技能，以启动独立的研究职业和计量专业知识，在半导体和材料行业的价值。该设备所实现的研究将使我们能够解决二维材料中亚纳米孔传输中未回答的问题，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下质量传输的理解，并支持研究开发具有高渗透率的膜，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.**