Mimicking human skin's functions to develop electronic skins has inspired tremendous efforts in design and synthesis of novel soft materials with simplified fabrication methods. However, it still remains a great challenge to develop electronically conductive materials that are both stretchable and self‐healable. Here it is demonstrated that a ternary polymer composite comprised of polyaniline, polyacrylic acid, and phytic acid can exhibit high stretchability (≈500%) and excellent self‐healing properties. The polymer composite with optimized composition shows an electrical conductivity of 0.12 S cm−1. On rupture, both electrical and mechanical properties can be restored with ≈99% efficiency in a 24 h period, which is enabled by the dynamic hydrogen bonding and electrostatic interactions. It is further shown that this composite is both strain and pressure sensitive, and therefore can be used for fabricating strain and pressure sensors to detect a variety of mechanical deformations with ultrahigh sensitivity. The sensitivity and sensing range are the highest among all of the reported self‐healable piezoresistive pressure sensors and even surpass most flexible mechanical sensors. Notably, this composite is prepared via a solution casting process, which potentially allows for large‐area, low‐cost fabrication electronic skins.

The development of a scalable, low-cost, and versatile biosensor platform for the sensitive and rapid detection of human metabolites is of great interest for healthcare, pharmaceuticals, and medical science. On the basis of hierarchically nanostructured conducting polymer hydrogels, we designed a flexible biosensor platform that can detect various human metabolites, such as uric acid, cholesterol, and triglycerides. Owing to the unique features of conducting polymer hydrogels, such as high permeability to biosubstrates and rapid electron transfer, our biosensors demonstrate excellent sensing performance with a wide linear range (uric acid, 0.07-1 mM; cholesterol, 0.3-9 mM, and triglycerides, 0.2-5 mM), high sensitivity, low sensing limit, and rapid response time (∼3 s). Given the facile and scalable processability of hydrogels, the proposed conductive hydrogels-based biosensor platform shows great promise as a low-cost sensor kit for healthcare monitoring, clinical diagnostics, and biomedical devices.

Near-field communication (NFC) labeling technology has been recently used to endow smartphones with nonline-of-sight sensing functions to improve the environment, human health, and quality of life. For applications in detecting food spoilage, the development of a sensor with high enough sensitivity to act as a switch for an NFC tag remains a challenge. In this Letter, we developed a nanostructured conductive polymer-based gas sensor with high sensitivity of Δ R/ R = 225% toward 5 ppm ammonia NH and unprecedented sensitivities of 46% and 17% toward 5 ppm putrescine and cadaverine, respectively. The gas sensor plays a critical role as a sensitive switch in the circuit of the NFC tag and enables a smartphone to readout meat spoilage when the concentration of biogenic amines is over a preset threshold. We envision the broad potential use of such intelligent sensing for food status monitoring applications in daily life, storage and supply chains.