EAGER: Manufacturing Nanocomposite Materials Using Ultrasound Directed Self-Assembly and Additive Fused Deposition Modeling

这一探索性研究（EAGER）早期概念奖的重点是了解基础科学，以证明一种制造工艺的可行性，该工艺将超声波定向自组装和添加剂熔融沉积建模相结合，以制造复杂的三维纳米复合材料。超声定向自组装组织纳米颗粒分散在流体成用户指定的模式使用外部超声波场。熔融沉积建模是一种基于挤压的增材制造工艺，可以从各种材料中制造出三维物体。目前的纳米粒子制模方法包括电场或磁场导向的自组装，这对纳米粒子的材料特性和形状有严格的要求。此外，需要高电场和磁场强度将粒子组织成用户定义的模式，这限制了纳米复合材料的尺寸可扩展性。超声波场允许操纵纳米粒子独立于其材料特性和尺寸，从而消除材料和尺寸的限制。由于超声波可以在宏观尺度上传播，因此，将超声波场穿透粘性液体所需的低场强与添加剂熔融沉积建模相结合，可以实现制造过程的尺寸可扩展性。该项目创造了在移动流体中超声波引导纳米粒子自组装的新知识，如熔融沉积建模。这个项目对研究生和本科生的教育有很大的帮助。研究成果融入研究生教学活动，并向科学界传播。这项EAGER研究的具体目标是展示一种结合超声定向自组装（DSA）和熔融沉积建模（FDM）制造工艺的概念验证，在该工艺中，分散在熔融FDM长丝中的纳米颗粒在从FDM三维打印机喷嘴挤出时被组织成特定的图案。为了实现这一目标，超声波换能器被集成到FDM打印机的打印喷嘴中，以便在熔化装载纳米颗粒的FDM长丝后控制纳米颗粒的图案/结构。超声波场的数值模拟决定了获得用户指定的纳米粒子模式所需的超声换能器的操作参数，考虑了材料的材料特性，包括长丝和纳米粒子。这种制造工艺允许使用FDM制造任何几何形状的3D宏观纳米复合材料，并使用超声DSA制造覆盖多个长度尺度的分层结构。研究的重点是纳米颗粒的圆形图案的制造。该项目评估了当FDM长丝固化并沉积在基板上时，圆形图案是否保留在原位。解决这一问题为设计超声DSA/FDM组合制造平台提供了知识。该项目允许PI推进纳米复合材料，增材制造和先进制造的知识库。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 EArly-concept Grants for Exploratory Research (EAGER) award focuses on understanding the basic science required to demonstrate feasibility of a manufacturing process that combines ultrasound directed self-assembly and additive fused deposition modeling to fabricate complex three-dimensional nanocomposite materials. Ultrasound directed self-assembly organizes nanoparticles dispersed in a fluid into user-specified patterns using an external ultrasound wave field. Fused deposition modeling is an extrusion based additive manufacturing process to make three-dimensional objects from a variety of materials. Current methods for patterning nanoparticles involve electric or magnetic field-directed self-assembly, which places strict requirements on the material properties and shape of the nanoparticles. In addition, the need for high electric and magnetic field strengths to organize particles into user-defined patterns limits dimensional scalability of the nanocomposite materials. Ultrasound wave fields permit the manipulation of nanoparticles independent of their material properties and dimensions, thus removing material and size restrictions. Additive fused deposition modeling in combination with the low field-strength required for an ultrasound wave field to penetrate viscous liquids enables dimensional scalability of the manufacturing process because ultrasound waves can propagate over macroscale distances. This project creates new knowledge in ultrasound directed self-assembly of nanoparticles in moving fluids such as in fused deposition modeling. This project contributes to the education of graduate and undergraduate students. The research results are integrated into graduate teaching activities and disseminated into the scientific community.The specific goal of this EAGER research is to show proof-of-concept of a combined ultrasound directed self-assembly (DSA) and fused deposition modeling (FDM) manufacturing process, in which nanoparticles dispersed in a molten FDM filament are organized into specific patterns as it extrudes from the FDM three-dimensional printer nozzle. To achieve this goal, an ultrasound transducer is integrated into the printing nozzle of an FDM printer to enable control of nanoparticle patterning/structuring after melting the FDM filament loaded with nanoparticles. A numerical simulation of the ultrasound wave field determines the ultrasound transducer operating parameters required to obtain user-specified patterns of nanoparticles, accounting for the material properties of both the filament and nanoparticles. This manufacturing process allows the fabrication of 3D macroscale nanocomposite materials of any geometry using FDM and with hierarchical structures that cover multiple length scales using ultrasound DSA. The research focus is on fabricating circular patterns of nanoparticles. The project evaluates whether the circular patterns remain in place when the FDM filament solidifies and is deposited on a substrate. Solving this problem provides the knowledge to devise a combined ultrasound DSA/FDM manufacturing platform. This project allows the PI to advance the knowledge base in nanocomposite materials, additive manufacturing and advanced manufacturing.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.