3D printing of jammed self-supporting microgels with alternative mechanism for shape fidelity, crosslinking and conductivity

Additive manufacturing technology is a growing field, which demands advanced chemistry and fabrication process if smart-materials are desired. Herein, the concept of jammed microgels designed with a new crosslinking method is introduced to be used in 3D-printing applications. Jammed microgels decorated with superficial hydrophobic segments and pure thermo-sensitive gelatin are applied as inks and exhibit shear-induced transition and fast recoverability, which are important for 3D-printing. The interaction of microgels within the as-extruded filaments and with the adjacent deposited layers guarantees shape-fidelity. After printing, a deep eutectic solvent (DES) formed from Arginine and Glycerol ([DES] Arg/Gly) is applied over the construct to trigger a chemical crosslinking reaction between epoxy and amine groups. The introduced [DES] Arg/Gly can play simultaneously two roles: (1) activator of covalent bond formation and (2) conducting agent. Generally, a variety of features including printability, rheological properties and shape-retention are dependent on the fraction of hydrophobic segments and the applied [DES] Arg/Gly concentration. Further, the main network percolation reaction follows a different strategy to achieve a sustainable printable system with biological, mechanical and physiological sustainability of the construct. These results open new possibilities to fabricate a wide range of adaptive platforms of smart materials with ease.