Nanopaper-based sensors with ultrahigh and stable conductance for wearable sensors and heaters

Conductors with high conductivity and flexibility are critical components of smart wearable electronics. However, the substrates of most reported flexible conductors are typically non-renewable and non-biodegradable, derived from petroleum-based synthetic polymers. Inspired by the ancient needling process in textiles, needling technology was introduced into the preparation of nanopaper-based sensors for the first time, a modular composite nanopaper-based electronic (MCPE) with an interlayer performance-enhancing structure was prepared by combining cellulose aerogel and liquid metal. Such a reinforcement structure can improve the interlaminar strength of the MCPE by 94.8 %, and the interlaminar strength of the modular connection by 39.2 %. The service life of the MCPE is greatly improved and its practical application scenarios are expanded. The MCPE has long-term durability (>6000 pressing/releasing cycles) and good initial conductivity (9.6 × 103 S cm−1). The MCPE exhibits unique pressure-insensitive behavior (ΔR/R0 < 0.02) up to 0.9 MPa. In addition, as a wearable sensor, MCPE can respond to pressure and deformation through a self-powered mode. When the MCPE is used as an electric heater, the temperature can reach 58 °C at 0.8 V. This nanopaper-based sensor with a reinforcement structure demonstrates unique pressure-insensitive behavior and provides a direct path to flexible electronics.