High performing piezoresistive MoS2/epoxy strain sensors for structural health monitoring

The integration of self-sensing and damage detection mechanisms is a critical task towards enhancing reliability of epoxy-based structures. Herein, epoxy/MoS2 composites with various MoS2 loadings were used as self-sensing materials for the first time in the literature. A three roll mill (TRM) was employed to exfoliate and disperse MoS2 in-situ in the epoxy resin. The morphology and dispersion of MoS2 nanoplatelets were examined by scanning electron microscopy. The incorporation of MoS2 not only improved the elastic modulus of epoxy resin but also endowed the resin with enough electrical conductivity to achieve self-sensing properties. The composites exhibited gauge factors of 48, 44 and 40 when reinforced with 1.89, 2.4 and 2.93 vol% MoS2 under tension. These gauge factors are higher than the ones reported from carbon material-reinforced epoxy composites. The semiconducting nature and 2D nanoplatelet-like structure of MoS2 flakes are key parameters for the high sensitivity of the final composites.