“All-in-one” polypyrrole pillar hybridization flexible membranes on multimodal tactile sensors for wearable energy-storage devices and human–machine interfaces

Abstract

We designed an “all-in-one” polypyrrole pillar hybridization flexible membrane for wearable energy-storage devices and human–machine interfaces (HMIs). The PPy pillar microarrays were an “elevated freeway” for enhancing electron/ion transfer and pressure sensing. The intercalated graphene/cellulose nanofibrils (RGO/CNFs) microstructure was a ground-staggered “road” network for mechanical support and charge adsorption. Based on this finely designed structure, a tactile sensor was developed to possess a sensitive response of current against various human signals, such as finger bending/sliding, swallowing, facial expression, and tremors. Application scenarios of HMIs could be expanded to interface instantiation, which, after assembly into a micro-supercapacitor, an area capacitance of 113 mF cm⁻² (vs. the whole device), an area energy density of 15.7 μW h cm⁻², and a power density of 0.25 mW cm⁻² were realized. Similarly, the MSC covered with an ice cube could be connected into a series configuration to power an LED, which comprised an anti-freezing gel electrolyte. The flexible membrane with a hierarchical structure demonstrated potential in wearable energy-storage devices and HMIs. Our methodology could be used to develop next-generation “soft” electronics.