MRI: Development of a Colloidal Force-Distance-Adsorption Apparatus for Particle Science Research and Education

凭借主要研究仪器项目的这一奖项，弗吉尼亚理工学院和州立大学将开发一种新的测量胶体力的实验工具。对这些力量的了解在材料科学、细胞生物学、土壤科学、废物处理和水净化、陶瓷工程、个人产品开发以及微电子行业的质量控制中都很重要。该仪器将结合原子力显微镜(AFM)和全内反射显微镜(TIRM)的能力，同时克服每种技术的大多数缺点。该仪器将提供一种新的能力：能够测量颗粒碰撞过程中的吸附等温线。原子力显微镜是目前使用最广泛的测量胶体力的方法。这种应用的一个主要问题是，颗粒和表面之间的分离不是测量的；它是间接推导出来的。利用这种装置，可以直接从激光在衬底/流体界面上全反射产生的逝去波的散射强度中获得分离。这种方法是基于TIRM技术的。TIRM技术将通过对散射的逝去波进行调制来改进。材料在表面的吸附是调节胶体作用力的主要方法，因此测定颗粒相互作用过程中的吸附是有用的。我们将开发一种使用吸附物上的荧光标记来测量碰撞过程中的吸附的技术。研究生和本科生将参与这个仪器开发项目。我们在日常生活中遇到的许多物体实际上都是由非常细的颗粒组成的。例如，砖、纸、衣服、中国、土壤、大多数食品、化妆品，甚至人类都是由小颗粒组成的。这些对象的物理属性(例如，刚度、流动性和可加工性)取决于粒子之间的力。创造新的和改进的产品的过程的一部分是操纵颗粒之间的力以获得所需的材料特性。操纵这些力量的第一步是测量它们。弗吉尼亚理工学院和州立大学将利用主要研究仪器项目的这一奖项，开发一种新的实验工具，用于测量作用在粒子上的力。新仪器将结合现有的技术，原子力显微镜的力探头和全内反射显微镜的距离探头，并通过使用分子的信号调制和荧光标记进行改进。一名研究生和本科生将参与这个仪器开发项目。

With this award from the Major Research Instrumentation program Virginia Polytechnic Institute and State University will develop a new experimental tool for measuring colloidal forces. An understanding of these forces is important in materials science, cell biology, soil science, waste disposal and water purification, ceramic engineering, the development of personal products, and in quality control in the microelectronics industry. The instrument will combine capabilities of atomic force microscopy (AFM) and total internal reflection microscopy (TIRM), while overcoming most of the drawbacks for each technique. The instrument will provide a new capability: the ability to measure adsorption isotherms during particle collisions. The atomic force microscope is currently the most widely used method for measuring colloidal forces. A major problem with this application is that the separation between the particle and the surface is not measured; it is derived indirectly. With this apparatus, the separation will be obtained directly, from the scattering intensity from an evanescent wave produced by totally reflecting a laser beam at the substrate/fluid interface. This approach is based on the TIRM technique. The TIRM technique will be improved through modulation of the scattered evanescent wave. The adsorption of material to surfaces is the main method by which colloidal forces can be modulated, so it is useful to determine adsorption during particle interactions. We will develop a technique for measuring adsorption during collisions using fluorescent tags on the adsorbates. Graduate and undergraduate students will participate in this instrument development project.Many of the objects that we encounter in everyday life actually consist of very fine particles. For example, bricks, paper, clothing, china, soil, most foods, cosmetics, and even humans are composed of small particles. The physical properties (e.g. stiffness, flow, and workability) of these objects depends on the forces between the particles. Part of the process of creating new and improved products is the manipulation of the forces between particles to obtain desirable material properties. The first stage of manipulating these forces is to measure them. With this award from the Major Research Instrumentation program Virginia Polytechnic Institute and State University will develop a new experimental tool for measuring the forces acting on particles. The new apparatus will combine existing techniques, the force probe from Atomic Force Microscopy and the distance probe from Total Internal Reflectance Microscopy, and incorporate improvements through the use of signal modulation and fluorescent tagging of molecules. A graduate student and undergraduate students will participate in this instrument development project.