Anisotropic silver nanowire dielectric composites for self-healable triboelectric sensors with multi-directional tactile sensitivity

Self-healable wearable devices with tactile directional sensitivity have attracted significant attention due to their damage-free sustainable and precise detection of directional body motions in various applications such as hand gesture monitoring and electrooculography (EOG) sensors. In this study, a self-powered triboelectric sensor with tactile directional sensitivity and self-healing property based on the dielectric multilayers of aligned silver nanowire (AgNW) composite gel sandwiched between self-healable polymers has been developed. Its output performances are superior to those of similar devices without the AgNW gel due to the stronger interfacial polarization of the dielectric multilayers and charge trapping by AgNWs. Moreover, the aligned AgNW composite gel possesses anisotropic dielectric properties, which enhances the contact direction-sensitive triboelectric performance of the sensor during rolling or rubbing motions. The fabricated sensor can be used in wearable EOG and electrocardiography applications because of the ability to monitor extremely weak blood pulse waves in the temporal artery around the human eye, while its directional force sensitivity allows differentiating eight eye movement directions. The successful use of the multilayered structure containing the self-healable and aligned AgNW composite gel as a triboelectric dielectric material opens a new avenue for designing self-healable wearable sensors with tactile directional sensitivity.