Multifunctional Poly(acrylic acid)/Chitosan nanoparticle network hydrogels with tunable mechanics

•A new strategy for combining hybrid double network hydrogels and nanoparticle network hydrgels was proposed.•Poly(acrylic acid)/chitosan nanoparticle network hydrogels with prominent mechanical properties was fabricated.•This hydrogel exhibited potential antibacterial activity, electrical conductivity, and anti-freezing property.•The reversible physical network enables the prepared hydrogel good self-recovery ability and fatigue resistance. Nanoparticle network hydrogels (NNHs) employ nanoparticles as key building blocks of hydrogel networks to provide excellent mechanical properties and multifunctionality. Herein, poly(acrylic acid)/chitosan nanoparticle network hydrogels (PAAc/CS NNHs) with prominent mechanical properties were fabricated using catechol functional methacryloyl chitosan-silver nanoparticles (CFMC-Ag NPs) as multifunctional nanoparticle crosslinkers. The PAAc/CS NNHs were composed of hybrid networks derived from CFMC-Ag NPs crosslinked PAAc and entangled chitosan (CS) chains. The mechanical properties of PAAc/CS NNHs were highly impacted by the concentration of CFMC-Ag NPs. A maximum tensile strength of 2.22 MPa, a compressive strength of 10.61 MPa, and a toughness of 5.57 MJ·m−3 were obtained at a nanoparticle concentration of 10 mg/mL. In addition, PAAc/CS NNHs exhibited great self-recovery performance and excellent fatigue resistance. It was demonstrated that PAAc/CS NNHs possessed antibacterial activity, electrical conductivity and anti-freezing capability. This strategy could be applied for the preparation of other multifunctional hydrogels with significant mechanical properties. [Display omitted]