Ultrasoft Self-Healing Nanoparticle-Hydrogel Composites with Conductive and Magnetic Properties

Recently, integration of two or more important properties into a hydrogel has been a challenge in the preparation of the multifunctional hydrogel. Herein, in order to impart conductive and magnetic properties to the self-healing PVA hydrogel at the same time, the nanofibrillated cellulose (NFC) was used as the substrate. The polyaniline was coated on the NFC surface by in situ chemical polymerization, and the MnFe2O4 nanoparticles were synthesized and loaded on the NFC by the chemical co-precipitation method. The multifunctional PVA hydrogel was prepared by incorporating the NFC/PAni/MnFe2O4 nanocomposites with the PVA hydrogel. The magnetic and conductive property tests of the multifunctional PVA hydrogel showed that the maximum saturation magnetization and conductivity were 5.22 emu·g–1 and 8.15 × 10–3 S·cm–1, respectively. Moreover, the multifunctional PVA hydrogel exhibited excellent self-healing and ultrasoft properties, which could be self-healed completely after the pieces of the hydrogel were put together for several minutes at room temperature. Due to the self-healing ability, conductivity, and magnetism, the novel hydrogel was expected to be used in many practical applications, such as electrochemical display devices, rechargeable batteries, and electromagnetic interference shielding. More importantly, we proved a facile template approach to the preparation of a stable polymer and nanoparticle composites using NFC as substrates that imparted different properties to hydrogels.