Acoustic-assisted 3D printing based on acoustofluidic microparticles patterning for conductive polymer composites fabrication

Multifunctional composites have been widely utilized in soft robots, electronics, batteries, and biomedicine. Meanwhile, several fabrication processes have been proposed to fabricate these functional composites with desired mechanical, electrical, magnetic, and thermal properties. However, patterning functional micro/nanomaterials such as particles, dots, wires, and fibers into complex designs with high spatial resolutions in a matrix remains a technical challenge. Herein, we present an acoustic-assisted 3D printing method enabled by standing surface acoustic waves (SSAWs). The proposed SSAWs-assisted patterning method produces diverse patterning forms of micro/nanomaterials and has almost no special requirements on micro/nanomaterials properties, indicating its great versatility and compatibility. Functional materials are assembled into desired stripe-like, net-like, and dot-like patterns. Multilayer composites with different patterns in each layer are even fabricated through a layer-by-layer printing process. To further demonstrate the potential of this 3D printing method, conductive polymer composite films with programmed electrical anisotropies are printed, yielding a maximum electrical conductivity of 827 S/m. The proposed acoustic-assisted patterning method makes the 3D printing of complex functional composites with customized properties possible, pushing the wide application of functional composites forward.