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

最近在增材制造方面的快速进展已经证明了其通过将微米或纳米颗粒包括到聚合物基复合材料中来定制所生产结构的局部和全局性质的巨大潜力。然而，当前的方法受到嵌入颗粒的精确空间控制的挑战的限制，嵌入颗粒通常具有不同的材料性质、尺寸和形状，使得粘性聚合物流体中的颗粒操纵困难。该合作研究奖将进行基础研究，以改变增材制造技术，该技术利用数字光处理进行光聚合印刷和声学全息术，以准确地“镊子”聚合物树脂中的微/纳米颗粒。该研究将极大地影响声学镊子，材料加工，超材料和生物材料等基础科学领域。此外，所研究的声全息增材制造技术将通过实现新型超材料来推进许多工程应用，例如，用于超声信号处理装置的网格状图案、用于飞机复合结构的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化微血管。通过教育和外联活动，该项目还将扩大代表性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声全息使能的增材制造机制，以制造包含不同微/纳米颗粒（如纤维素纳米纤丝、碳基颗粒和细胞等）的高分辨率、通用图案的多功能复合材料。一种声全息摄影术的粒子图案化机制将建立在粘性树脂构建和重新配置通用粒子图案通过研究频率复用-基于的多频声场动态控制方法。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化过程的理论模型。接下来，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技术相融合，以创建一种用于可扩展增材制造的通用高分辨率设备。然后，该装置将被用来开发和研究新型多功能复合材料，如拓扑超材料复合材料含有周期性格子状图案的微颗粒。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增材制造复合材料的不同性能的影响，包括各向异性弹性，声学带隙，狄拉克锥和拓扑状态等。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.