(221c) 3D Printing of Thermoset/Mxene Composites with Layered Hierarchies

3D printing of composites has many challenges, such as feedstock quality, printing parameter control, and structural design during layered additive manufacturing. Current 3D printing platforms include resin-based, filament-based, powder-based, and ink- or solution-based strategies. However, none of these 3D printing methods can achieve nanoscale structural controls, especially when nanoparticles are involved. Therefore, this research reports a hybrid manufacturing combining the 3D printing of stereolithography (SLA) and direct ink writing (DIW) to achieve the manipulation of nanoscale particle conformation. To demonstrate the capability of managing nanoscale features, we synthesized the MXene (i.e., Ti₃C₂T_x) nanoparticles via alloying metallurgy and etching dynamics. These two-dimensional flakes have a higher bending modulus than commonly used graphene and are expected to retain their 2D morphologies upon flow-assisted distribution. This distribution of nanoparticles was facilitated by (i) first the printing of surface patterns via SLA-printed topology control, and (ii) second the deposition of rheology-controlled nanoparticle suspensions. During the ink writing procedures, the secondary forces directed the anchoring and stacking of MXene with flat surfaces compliant with surface patterning. As a result, these composites display enhanced mechanical robustness, anisotropic electrical conductivity, and improved sensing capabilities, therefore useful for structural composites, microelectronics, thermal dissipators, and metasurfaces.