Additive-Free MXene Liquid Crystals and Fibers

Area of Science:

• Materials Science
• Nanotechnology
• Colloid Science

Background:

• Two-dimensional (2D) materials like MXenes offer unique properties.
• Liquid crystalline (LC) phases in 2D material dispersions allow for ordered 3D structures.
• Controlling self-assembly in nanomaterial inks is crucial for advanced material fabrication.

Purpose of the Study:

• To report the first observation of self-assembled liquid crystalline (LC) phases in aqueous Ti3C2 MXene inks without additives.
• To investigate the factors influencing LC phase transitions in MXene dispersions.
• To demonstrate the fabrication and properties of MXene fibers derived from LC phases.

Main Methods:

• Experimental observation of liquid crystalline phases in Ti3C2 MXene aqueous dispersions.
• Analysis of the influence of MXene flake aspect ratio on phase transition concentration.
• Wet-spinning technique for fabricating MXene fibers from nematic LC phases.
• Characterization of electrical conductivity and volumetric capacitance of the produced fibers.

Main Results:

• Self-assembled nematic liquid crystalline (LC) phases were observed in Ti3C2 MXene inks without external agents.
• The transition concentration to the nematic phase depends on the MXene flake aspect ratio.
• Wet-spun Ti3C2 MXene fibers exhibit high electrical conductivity (~7750 S cm-1) and volumetric capacitance (~1265 F cm-3).
• The LC behavior is also observed in other MXene compositions and organic solvents.

Conclusions:

• MXene inks can spontaneously form liquid crystalline phases, enabling additive-free fabrication of aligned structures.
• The resulting MXene fibers possess superior electrical and electrochemical properties, suitable for energy storage devices.
• The widespread LC behavior of MXenes suggests broad potential for creating advanced functional materials and devices.