Ultrasound directed self-assembly of non-periodic patterns of particles

该奖项支持研究所需的理论和实验基础，组织和定向分散在流体介质中的颗粒成特定的模式，使用与超声波场相关的力。该研究特别关注使用多频而不是单频超声波场来组装任意的非周期性粒子图案。许多工程应用可以从这项研究中受益，包括颗粒和细胞分离过程，悬浮液的混合和分散控制，非接触式颗粒操作以及具有定制特性的工程复合材料的制造。基础理论，以优化参数（振幅，相位，和一组频率），以组装在多个维度的球形粒子的任何模式将被开发。通过与弗吉尼亚理工大学工程多样性增强中心合作，并为计算机和技术夏令营和妇女预览周末做出贡献，将促进代表性不足的群体在STEM教育中的广泛参与。该奖项的研究目标是从理论上推导和实验验证科学基础，使分散在流体介质中的颗粒能够组织和定向成任何周期性或非周期性图案，利用与多频超声波场相关联的力。将进行一项理论和实验研究，其中包括解决这一问题的四个技术要点。它们包括：1）推导球形和高纵横比颗粒的多频超声定向自组装（DSA）理论，2）多频超声DSA理论的实验验证，3）多频超声DSA与瓮聚合AM的集成以证明制造具有定制性质的聚合物基质复合材料的概念验证，以及4）将从这项研究中获得的知识打包在一个开源软件工具中，以便其他用户可以使用。总之，这四个研究重点的结果将描述基于多频波场的超声DSA的物理基础。该奖项的结果将促进外场DSA方法的发现、实施和部署，以及多相混合物中颗粒组织和方向的控制。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

This award supports research into the theoretical and experimental foundation required to organize and orient particles dispersed in a fluid medium into specific patterns, using the forces associated with an ultrasound wave field. The research specifically focuses on using multi-frequency rather than single-frequency ultrasound wave fields to enable assembling arbitrary, non-periodic patterns of particles. A host of engineering applications could benefit from this research, including particle and cell separation processes, mixing and dispersion control of suspensions, non-contact particle manipulation, and manufacturing of engineered composite materials with tailored properties. Fundamental theory to optimize the parameters (amplitude, phase, and set of frequencies) to assemble any pattern of spherical particles in multiple dimensions will be developed. Broadening participation of underrepresented groups in STEM education will be promoted by partnering with the Center for Enhancement of Engineering Diversity at Virginia Tech and contributing to the Computers and Technology summer camp and the Women’s Preview Weekend.The research objective of this award is to theoretically derive and experimentally validate the scientific foundation that enables organizing and orienting particles dispersed in a fluid medium into any periodic or non-periodic pattern, utilizing the forces associated with a multi-frequency ultrasound wave field. A theoretical and experimental study will be implemented that covers four technical thrusts to solve this problem. They include: 1) derivation of multi-frequency ultrasound directed self-assembly (DSA) theory for both spherical and high aspect ratio particles, 2) experimental validation of the multi-frequency ultrasound DSA theory, 3) integration of multi-frequency ultrasound DSA with vat-polymerization AM to demonstrate proof-of-concept of manufacturing polymer matrix composite materials with tailored properties, and 4) packaging the knowledge resulting from this research in an open-source software tool to make it accessible for other users. Together, the outcomes of these four research thrusts will describe the physical underpinnings of ultrasound DSA based on multi-frequency wave fields. The results of this award will advance discovery, implementation, and deployment of external field DSA methods, and control of organization and orientation of particulates within multiphase mixtures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.