Polyvinyl alcohol–reinforced silk nanofiber/MXene composite aerogel as wearable sensors for detecting human motion

Abstract

Flexible pressure sensors are known for their excellent comprehensive performance, making them suitable for a wide range of applications, including in human–machine interfaces, health monitoring, motion detection, wearable electronics, medical devices, and soft robotics. However, the preparation of silk nanofibers (SNFs)-based aerogel sensors with optimal resilience remains challenging. Herein, the SNF/ polyvinyl alcohol (PVA)/MXene composite aerogel was prepared via freeze-drying using SNF, MXene and PVA as raw materials. In this study, PVA was innovatively used as a binder to connect dispersed SNFs, which improved the resilience and mechanical properties of aerogel. The resulting composite aerogel can function as a pressure sensor that exhibits excellent efficacy owing to the synergies among its various components, achieving an impressive gauge factor of 24.61 at a compression strain of 40 %–50 %. The composite aerogel–based sensors also exhibited a rapid response time (load 100 ms, recovery 200 ms), and good stability (1000 cycles). They demonstrated a quick response to pressure and strain signals, enabling them to accurately monitor various human activities such as sound detection, wrist and finger movements, and knee bending.