Ascorbic acid-induced fiber-scrolling of titanium carbide Ti(3)C(2)T(x) MXene

Changing the morphology of two-dimensional materials often offers an efficient and effective means to exploit their electronic and mechanical properties. Two-dimensional materials such as graphene can be scrolled into one-dimensional fibers via simple sonication. Unfortunately, scrolling MXene nanosheets into fibers is quite challenging, especially Ti(3)C(2)T(x) composed of three layers of titanium atoms and two layers of carbon atoms. Herein, we report a new method to fabricate MXene fibers via ascorbic acid (AA) induced scrolling of Ti(3)C(2)T(x) nanosheets. An unusual AA-Ti(3)C(2)T(x) interaction is discovered in that intercalated AA molecules bind to and interact with the Ti(3)C(2)T(x) surface in the form of a hydrogen bonding-bonded assembly instead of as individual molecules, and a sheet-scrolling mechanism is proposed based on this interaction. The as-obtained MXene fibers exhibit a compact cross-section, and the diameter can be tailored from hundreds of nanometers to several micrometers through tuning the MXene/AA ratio. Moreover, the storage modulus of the MXene-fiber sponge attains its maximum value of ∼1 MPa when a unique morphology comprising both fibers and not-yet-scrolled sheets is presented. This work offers a new strategy of fiber-shaping MXenes for applications in structural composites and flexible electronics.