A simple, validated approach for design of two-dimensional periodic particle patterns via acoustophoresis

• Published in: Materials & design 2023-08, Vol.232, p.112165, Article 112165
• Main Authors: Johnson, Keith E., Melchert, Drew S., Armstrong, Emilee N., Gianola, Daniel S., Cobb, Corie L., Begley, Matthew R.
• Format: Article
• Language: English
• Subjects: Acoustic focusing; Architected materials; ENGINEERING; Gor’kov potentials; Hierarchical microstructure; Periodic patterns; Ultrasonic standing wave
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2023.112165

[Display omitted] •A fast, simple, and user-friendly method to predict the organized patterns taken on by high loadings of particles in acoustic fields.•This method is validated both through more complex discrete particle simulations and through experiments.•Utility of this method is highlighted by predicting and demonstrating new novel multi-scale hierarchical microstructures and predicting new 3D structures. Two-dimensional patterning of microparticles enables a wide range of functional materials, including patterned energy storage electrodes, flexible electronics, and sensor arrays. Particle patterning via acoustics offers an attractive path to generate a wide variety of 2D periodic patterns that introduce tailorable hierarchical porosity, useful for controlling surface area, transport distances, and other properties. This method is most effective with micron scale particles and patterns of tens to hundreds of microns. To enable systematic exploration of the broad design space for such patterns, this work develops a model of 2D and 3D assembly of particles at high loadings and validates the obtained patterns against both experiments and more computationally intensive modeling techniques. Using this simple model, connections are mapped between input parameters (like actuation conditions, particle volume fraction, material properties) and output geometrical features (like void size and shape, pattern connectivity, and surface area) so that they can be tailored to given applications. The utility of this simple model is illustrated by predicting and then experimentally demonstrating new hierarchical patterns resulting from multiple waves of different frequencies interacting. These multiscale patterns offer the potential to lift the limits on surface area, diffusion distances, and other features.