Electrospinning Superhydrophobic Flexible Wearable Sensor of CPU@MXene@SiO2 with High Sensing Sensitivity

Abstract

Flexible wearable sensors have garnered significant attention for their potential applications in electronic skins, health monitoring, and smart devices. However, current flexible sensors often suffer from limitations, such as low sensitivity and inadequate resistance to mechanical and chemical degradation. To address these issues, this study presents a CPU@MXene@SiO₂ superhydrophobic flexible sensor fabricated using a combination of electrospinning and dip-coating techniques. This sensor features a sandwich structure composed of an electrospinning fiber membrane (CPU) substrate, an MXene conductive coating, and a superhydrophobic SiO₂ coating. Based on the fabricated sensor, strain and piezoresistive sensors were further assembled to systematically investigate the effects of micro/nanostructures and chemical compositions on wettability and sensing performance. Experimental results demonstrated that the CPU@MXene@SiO₂ sensor exhibited outstanding comprehensive properties including high mechanical strength, superhydrophobicity (CA > 155°, RA < 3°), low adhesion force (33 μN) with water, high sensing sensitivity (gauge factor up to 4922.6), and fast response (response time of 94 ms). Moreover, to validate its potential for large-scale applications, a complete data acquisition system based on an STM32 microcontroller and a mobile application was designed and developed. A 4 × 4 sensor array was successfully fabricated and tested. This sensor demonstrates promising and attractive applications in wearable devices and human-machine interaction, offering an efficient design strategy for constructing robust and highly sensitive flexible sensors.

Keywords: CNT; MXene; electrospinning; flexible sensor; superhydrophobicity.