Signal-Independent and Interference-Resistant All-MXene Flexible Pressure-Temperature Dual-Mode Sensor

Flexible, skin-like sensors are capable of converting various external stimuli into measurable electrical signals, crucial for advancing human-computer interaction and wearable health monitoring devices. Previous research on flexible smart sensing elements has primarily targeted single sensing functions, leaving the quest for integrated sensors capable of monitoring multiple signals largely unmet. In this article, a signal-independent and interference-resistant pressure-temperature dual-mode sensor was fabricated by using a synergistic approach of structure and material design. A temperature-sensitive layer with a high-temperature coefficient was prepared by introducing metal-organic framework material (MOF)-MXene into polyurethane (PU), and the dual-mode sensor was subsequently obtained by assembling it with silanized MXene (S-MXene)/polyvinylidene fluoride (PVDF) composite as the encapsulating material and the pressure sensing layer. Fabric electrodes have small longitudinal dimensions as well as favorable compressibility and are well suited for the preparation of the miniature integrated sensor. Remarkably, the sensor demonstrates independent high-performance detection of both temperature and pressure signals. In terms of temperature sensing, the device has an average sensitivity of −3.6%<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot ^{\circ }$ </tex-math></inline-formula>C<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text {-1}}$ </tex-math></inline-formula> and a resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1~^{\circ }$ </tex-math></inline-formula>C, which is better than the most sensors based on thermally sensitive semiconductor materials. The sensor has excellent resistance to stress and pressure interference, which is promising for application in the detection of human physiological signals. While pressure sensing, the sensor has excellent overall performance, such as high sensitivity (1.02 kPa<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text {-1}}$ </tex-math></inline-formula>), skin-like rapid response time (40 ms), and ultrahigh cyclic stability (20000 cycles). Benefiting from the smaller temperature coefficient of the dielectric composite material, the sensor is insensitive to temperature within the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20~^{\circ }$ </tex-math></inline-formula>C–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50~^{\circ }$ </tex-math></inline-formula>C.