Recent progress in acoustic field-assisted 3D-printing of functional composite materials.

Acoustic forces are an attractive pathway to achieve directed assembly for multi-phase materials via additive processes. Programmatic integration of microstructure and structural features during deposition offers opportunities for optimizing printed component performance. We detail recent efforts to integrate acoustic focusing with a direct-ink-write mode of printing to modulate material transport properties (e.g. conductivity). Acoustic field-assisted printing, operating under a multi-node focusing condition, supports deposition of materials with multiple focused lines in a single-pass printed line. Here, we report the demonstration of acoustic focusing in concert with diffusive self-assembly to rapidly assembly and print multiscale, mm-length colloidal solids on a timescale of seconds to minutes. These efforts support the promising capabilities of acoustic field-assisted deposition-based printing to achieve spatial control of printed microstructures with deterministic, long-range ordering across multiple length scales.