Synchronously Enhancing Mechanical Strength and Conductivity of MXene Nanofluidic Fibers with Multivalent Ion Crosslinking

Developing high-performance nanofluidic fibers with synergetic ionic and electric conductivities is promising for human-machine interface interaction. In such a scenario, inter- and intra-forces in constituent flakes are recognized as crucial factors in determining the derived nanofluidic fiber performance. In this work, the rheological properties of Ti3C2Tx MXene solution are systematically optimized by regulating the electrostatic interaction via introducing multivalent metal cations. As a result, such multivalent cations trigger ionic crosslinking and remarkably strengthen the interaction force between nanosheets, which even forms into a tight fiber-shaped gel network. A series of cations, such as K+, Na+, Mg2+, Zn2+, and Al3+, are introduced to enhance the ionic cross-linking between interconnected flakes. The thus-prepared Zn2+-Ti3C2Tx fiber exhibits a remarkable electrical conductivity of 11 200 S cm-1, a tensile strength of 252 MPa, and an ionic conductivity of 2.51 x 10-3 S cm-1. This multivalent cation crosslinking strategy could offer some insights into developing functional nanofluidic fibers for wearable or healthcare applications. The rheological properties are optimized by introducing multivalent cations to modulate the electrostatic interaction force between nanosheets in Ti3C2Tx dope and prepared Zn2+-Ti3C2Tx fibers with a conductivity of 11 200 S cm-1, a tensile strength of 252 MPa, and an ionic conductivity of 2.51 x 10-3 S cm-1 by microfluidic spinning. image