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

近年来，增材制造技术的迅速发展表明，通过在聚合物基复合材料中加入微或纳米颗粒，增材制造在定制生产结构的局部和全局特性方面具有巨大潜力。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特性、尺寸和形状，使得颗粒在粘性聚合物流体中的操作变得困难。该合作研究奖将进行基础研究，以改造一种增材制造技术，该技术利用数字光处理技术进行光聚合印刷和声全息技术，以精确地“镊子”聚合物树脂中的微/纳米颗粒。该研究将对声镊、材料加工、超材料、生物材料等基础科学领域产生重大影响。此外，所研究的声全息增材制造技术将推动许多工程应用，通过实现新型超材料，例如，用于超声信号处理设备的晶格状图案，用于飞机复合材料结构定制修复的基于纤维素的增强结构，或用于个性化仿生骨组织再生的图案微血管。通过教育和推广活动，该项目还将扩大代表性不足的少数民族的参与，改善STEM教育，并增加公众对科学技术的参与。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声全息技术支持的增材制造机制，以制造多功能复合材料，该复合材料包含高分辨率，多种微/纳米颗粒的多功能模式，如纤维素纳米原纤维，碳基颗粒和细胞等。首先，通过研究基于频率复用的多频声场动态控制方法，建立基于声全息的粘树脂多用途粒子模式构建和重构机制。声波与粘性树脂中颗粒的相互作用将通过颗粒图像测速和声场扫描来揭示，并将开发和验证用于快速预测颗粒图案过程的理论模型。接下来，基于声全息的粒子图案技术将与基于数字光处理的光聚合相融合，为可扩展的增材制造创造一种多功能、高分辨率的设备。然后，该装置将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图案的拓扑超材料复合材料。将利用理论和实验方法进一步发现不同周期粒子模式对增材制造复合材料不同性能的影响，包括各向异性弹性、声波带隙、狄拉克锥和拓扑状态等。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。

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.