Two-dimensional (2D) material-based hydrogels have been widely utilized as the ink for extrusion-based 3D printing in various electronics. However, the viscosity of the hydrogel ink is not high enough to maintain the self-supported structure without architectural deformation. It is also difficult to tune the microstructure of the printed devices using a low-viscosity hydrogel ink. Herein, by mimicking a phospholipid bilayer in a cytomembrane, the amphiphilic surfactant nonaethylene glycol monododecyl ether (C12E9) was incorporated into MXene hydrogel. The incorporation of C12E9 offers amphiphilicity to the MXene flakes and produces a 3D interlinked network of the MXene flakes. The 3D interlinked network offers a high-viscosity, homogenized flake distribution and enhanced printability to the ink. This ink facilitates the alignment of the MXene flakes during extrusion as well as the formation of the aligned micro- and sub-microsized porous structures, leading to the improved electrochemical performance of the printed microsupercapacitor. This study provides an example for the preparation of microelectronics with tunable microstructures.
Keywords: 3D printing; MXene; aligned flakes; microsupercapacitor; viscoelastic ink.