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

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.