Tunable Fabrication of Conductive Ti₃C₂T_<i>x</i> MXenes via Inflating a Polyurethane Balloon for Acute Force Sensing

Abstract

Conductive microwrinkles present a superior performance in ultrasensitive sensing, smart controlling, as well as energy conservation because of their unique structures. These wrinkles are usually prepared by the deposition of a thin conductive stiff layer on a soft substrate under a certain strain. However, traditional conductive materials may encounter some deficiencies, such as fragility or poor dispersity, in any solvent. To promote the applicability of conductive microwrinkles, here, we adopt a new two-dimensional nanomaterial Ti₃C₂T_<i>x</i> MXene as the conductive stiff layer to construct the microwrinkles. By combining the spraying and inflating techniques, the hierarchical complex and delicate Ti₃C₂T_<i>x</i>-polyurethane (Ti₃C₂T_<i>x</i>-PU) microwrinkles have become facilely available. The characteristic wavelength and amplitude of the microwrinkles could be easily adjusted by altering the inflating height of the PU film or the spraying volume of the Ti₃C₂T_<i>x</i> solution. Because the as-prepared Ti₃C₂T_<i>x</i> wrinkles could sensitively generate deformation inducing a resistance change under a force, these structures are also assembled to detect the applied force. The Ti₃C₂T_<i>x</i> force sensors showed quick response to a tiny force and stable reliability over hundreds of cycles, which hold a promising potential to monitor or employ the microforce.