Super high-strength and tough collagen/PVA conductive hydrogel via phytic acid sodium-induced self-assembly for multifunctional sensors

Sodium phytate boosts the hydrogel's tensile strength from 36 kPa to 10.3 MPa (>280-fold) with a toughness of 51.5 MJ/m³. • The PCP hydrogel enables strain (0–800%) and temperature (−20 °C to 50 °C) sensing with a fast response time of ∼205 ms. • The PCP hydrogel possesses excellent flame retardancy, achieving a high LOI value of 47% Supramolecular hydrogels assembled through weak non-covalent interactions face major challenges in achieving high strength and conductivity for sensor applications. Molecular-level engineering to enhance interchain interactions offers a promising solution. Herein, a strong and tough conductive hydrogel is fabricated by introducing phytic acid sodium salt (PAS) into a collagen/polyvinyl alcohol (PVA) matrix via freeze-thaw and salting-out methods. Mechanistic analyses indicate that the enhanced network arises from PAS-induced formation and densification of multiple physical interactions, including hydrogen bonding, electrostatic interactions. The optimized hydrogel exhibits a tensile strength of ≈10.3 MPa, a toughness of ≈51.5 MJ/m 3 , and stretchability >700%, ranking among the strongest collagen/PVA hydrogels reported to date. Moreover, the hydrogel exhibits stable ionic conductivity, enabling its application as a multifunctional strain sensor for human activity monitoring, Morse code transmission, and temperature detection. This work provides a versatile and biocompatible platform for flexible electronics and wearable devices. Download: Download high-res image (232KB) Download: Download full-size image