Mechanically robust, stretchable and environmentally adaptable organohydrogels with cross-linked fibrous structure for sensory artificial skins

Abstract

Hydrogels are promising materials for fabricating sensory artificial skins (SASs), but their mechanical properties and environment adaptability are often limited, leading to restricted performances of SASs. In this work, mechanically robust, stretchable and environment adaptable organohydrogels with cross-linked fibrous structure are designed and constructed. The organohydrogels are prepared by introducing doped polyaniline (PANI) into cross-linked fibrous mats of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA). Cross-linked PAA-PVA mat works as skeleton to account for the mechanical robustness while PANI serves as the conductive component to achieve mechanosensing functionality. Due to the unique structure, the resultant organohydrogels, being denoted as PAA-PVA/PANI organohydrogels, exhibit high tensile strength (5.06 MPa), stretchability, fatigue resistance and excellent environment adaptability (anti-freezing, anti-drying and swelling resistance). SASs of such organohydrogels have achieved a gauge factor of 1.81, a sensing range of 0–70 %, a response time of 0.28 s and a reversible sensing in more than 2,000 cycles. In addition, SASs are further attempted in monitoring diverse human motions and physiological activities, such as joint bending, muscle motion and pulse. Overall, this work has provided promising soft materials for future SASs that work properly under complicated environmental conditions.