Biocompatible and robust MoS2@silk fibroin/PVA composite films for wearable flexible strain-gauge sensors

Abstract

This paper utilizes an improved intercalation exfoliation and liquid-phase coating approach to effectively fabricate two-dimensional molybdenum disulfide van der Waals thin films on silk fibroin/polyvinyl alcohol substrate (MoS₂@SF/PVA), which are then integrated into highly flexible, sensitive, and biocompatible piezoresistive strain-gauge sensors. This methodology is conducive for large-scale production, characterized by low production costs and high flexibility in terms of substrate selection. Experimental findings reveal that the as-fabricated sensor achieves peak sensitivity with a MoS₂ layer thickness of 80 nm, boasting a high gauge factor (GF) of up to 290 and a resistance reduction of only 6～7% after enduring 3000 testing cycles. Ultimately, the remarkable compatibility of silk fibroin biomaterials with skin allows for this flexible piezoresistive strain-gauge sensor to seamlessly adhere to human skin, without requiring any additional measures or imposing any discomfort. It proficiently captures the subtle surface texture of the skin and accurately senses human pulse signals, underscoring its considerable potential for innovative applications within the field of flexible electronics.