Collaborative Research: Acoustic Holography Enabled Additive Manufacturing of High-resolution Multifunctional Composites

近年来，添加剂制造领域的迅速发展表明，通过将微米或纳米颗粒加入到聚合物基复合材料中，它在调整所生产结构的局部和全局性能方面具有巨大的潜力。然而，目前的方法受到嵌入颗粒的精确空间控制挑战的限制，这些颗粒通常具有不同的材料属性、大小和形状，使得在粘性聚合物流体中操纵颗粒变得困难。这项合作研究奖将进行基础研究，以转化一种添加剂制造技术，该技术利用数字光处理进行光聚合印刷和声全息，以准确地在聚合物树脂中“钳制”微/纳米颗粒。这项研究将对声波镊子、材料加工、超材料和生物材料等基础科学领域产生重大影响。此外，所研究的声全息添加剂制造技术将推动许多工程应用，使新型超材料包括用于超声信号处理设备的晶格状图案、用于定制修复飞机复合材料结构的纤维素基增强结构，或用于个性化仿生骨组织再生的图案化微血管。通过教育和外联活动，该项目还将扩大代表不足的少数群体的参与，改善STEM教育，并增加公众对科学和技术的参与。该项目的多学科性质将为研究生和本科生提供独特的学习和培训机会。本研究的总体目标是了解一种基于声全息的添加剂制造机制，以制备包含多种微/纳米颗粒的高分辨率、多功能图案的多功能复合材料，如纤维素纳米纤维、碳基颗粒和细胞等。首先，通过研究基于频率复用的动态控制多频声场的方法，建立基于声全息的颗粒图案形成机制，以构建和重新配置粘性树脂中的多功能颗粒图案。通过粒子图像测速和声场扫描揭示了声波与粘性树脂中粒子的相互作用，建立并验证了快速预测粒子图案化过程的理论模型。下一步，基于声全息的颗粒图案化技术将与基于数字光处理的光聚合相融合，创建一种多功能、高分辨率的设备，用于可扩展的添加剂制造。然后，该装置将被用于开发和研究新型多功能复合材料，如含有周期性晶格状微粒子图案的拓扑超材料复合材料。理论和实验方法将被用来进一步发现不同的周期性颗粒模式对添加制造的复合材料的不同性能的影响，包括各向异性弹性、声带隙、狄拉克圆锥和拓扑态等。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Recent swift advances in additive manufacturing have demonstrated its great potential in tailoring the local and global properties of produced structures by including micro- or nano-particles into polymer matrix composites. However, current approaches have been limited by the challenge in precision spatial controls of embedded particles, which usually have diverse material properties, sizes, and shapes, making particle manipulation in a viscous polymer fluid difficult. This collaborative research award will conduct fundamental research to transform an additive manufacturing technology that leverages digital light processing for photopolymerization printing and acoustic holography to accurately “tweeze” micro/nano-particles in a polymer resin. The research will greatly impact basic science fields in acoustic tweezers, materials processing, metamaterials, and biomaterials, etc. Moreover, the studied acoustic holography additive manufacturing technology will advance many engineering applications through enabling novel metamaterials containing, e.g., lattice-like patterns for ultrasonic signal processing devices, cellulose-based reinforced architectures for customized repair of aircraft composite structures, or patterned micro-vessels for personalized biomimetic bone tissue regeneration. Through education and outreach activities, this project will also broaden the participation of underrepresented minorities, improve STEM education, and increase public engagements with science and technologies. The multidisciplinary nature of this project will provide unique learning and training opportunities for graduate and undergraduate students. The overall objective of this research is to understand an acoustic holography enabled additive manufacturing mechanism to fabricate multifunctional composites that contain high-resolution, versatile patterns of diverse micro/nano-particles such as cellulose nanofibrils, carbon-based particles, and cells, etc. First, an acoustic holography-based particle patterning mechanism will be established to construct and reconfigure versatile particle patterns in viscous resins by studying a frequency multiplexing-based method for dynamically controlling multifrequency acoustic fields. Acoustic wave interactions with particles in viscous resins will be uncovered through particle image velocimetry and acoustic field scanning, and a theoretical model for rapid prediction of the particle patterning process will be developed and validated. Next, the knowhow of the acoustic holography-based particle patterning will be fused with the digital light processing-based photopolymerization to create a versatile, high-resolution apparatus for scalable additive manufacturing. Then, the apparatus will be utilized to develop and study novel multifunctional composites such as topological metamaterial composites containing periodic lattice-like patterns of micro-particles. Both theoretical and experimental methodologies will be utilized to further discover the effects of different periodic particle patterns on different properties of additively manufactured composites, including anisotropic elasticity, acoustic band gaps, Dirac cones, and topological states, etc.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.