Hybrid 3D printing for highly efficient nanoparticle micropatterning

Fused deposition modeling (FDM) 3D printing often generates inevitable surface phenomena/defects called the "staircase effect," which includes the anisotropic material texture, rough surface topology, and interlayer voids. Besides, the staircase morphology (i.e., interlayer microchannel dimensions and surface roughness) can be well-controlled with essential printing parameters, for example, the layer height and print orientation. Here, staircase surface defects generated from FDM 3D printing were utilized as the confined environment to directly assemble 2D nanoparticles (NPs) of MXene as long-range patterned microstructures through a combination with simple direct ink writing (DIW) 3D printing. Based on the layer-by-layer deposition procedure, Mxene NPs were patterned into a microfilm with a parallelly stacked morphology by combining the confinement effect from surface microchannels, MXene ink quantity control, and NP-substrate interactions. These commonly regarded surface defects (i.e., the staircase effect) from 3D printing demonstrated the potential for large-scale anisotropic patterning of a wide variety of NPs and biomolecules via simple microfluidic forces for structural reinforcement, thermal sensing, microelectronic devices, optical imaging, wireless data transportation, and metasurface applications.