Hierarchically Structured MXene Nanosheets on Carbon Sponges with a Synergistic Effect of Electrostatic Adsorption and Capillary Action for Highly Sensitive Pressure Sensors

A highly sensitive pressure sensor with nanoscale features was developed based on the gradient concentration of Ti 3 C 2 T x (MXene). The fabrication strategy involved electrostatic adsorption and capillary action utilizing a carbonized sponge as the substrate. In this approach, hexadecyl trimethyl ammonium bromide (CTAB) was added dropwise to the bottom of the carbonized melamine sponge, facilitating the self-assembly of MXene and achieving a gradient attachment of conductive fillers onto the substrate. Furthermore, a layer of polyvinyl alcohol fibers was electrospun between the sensor bottom and the electrode to enhance sensor sensitivity. The pressure-sensitive sensor prepared by this method exhibited an exceptionally strong response within the pressure range of 0–3 kPa. It demonstrated an ultrahigh sensitivity of 381.91 kPa –1, with a rapid deformation response of 100 ms and a quick recovery response of 30 ms. Notably, the sensor also demonstrated outstanding durability, enduring 8000 loading–unloading cycles without performance degradation. Moreover, it achieved a minimum detection limit as low as 0.1 Pa. Finite element numerical analysis confirmed that the MXene/CTAB/CMF composite prepared using this approach exhibited superior sensing performance under similar deformation conditions. Importantly, this pressure sensor’s exceptional sensing capabilities extended to detecting various physiological signals in the human body and daily work scenarios. When integrated with a microprocessor, it accurately processed complex data sets, highlighting its great potential for practical applications.