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

该奖项支持对理论和实验基础的研究，这些研究需要利用与超声波场相关的力来组织和定向分散在流体介质中的颗粒，使其形成特定的模式。这项研究特别侧重于使用多频而不是单频超声波场来组装任意的、非周期性的粒子模式。许多工程应用都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，非接触颗粒操作，以及具有定制性能的工程复合材料的制造。将发展优化参数（振幅、相位和频率集合）的基本理论，以在多个维度上组装任何球形粒子的图案。通过与弗吉尼亚理工大学工程多样性增强中心合作，并为计算机与技术夏令营和女性预览周末做出贡献，将扩大代表性不足群体对STEM教育的参与。该奖项的研究目标是通过理论推导和实验验证科学基础，利用与多频超声波场相关的力，将分散在流体介质中的颗粒组织和定向成任何周期或非周期模式。将实施一项理论和实验研究，涵盖四个技术重点来解决这个问题。它们包括:1)推导了球形和高长径比颗粒的多频超声定向自组装（DSA）理论，2)多频超声定向自组装理论的实验验证，3)多频超声定向自组装与增值聚合AM的集成，以证明制造具有定制性能的聚合物基复合材料的概念验证。4)将研究所得的知识打包到一个开源软件工具中，以便其他用户可以访问。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。该奖项的成果将促进外部场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。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

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.