Strong and tough cellulose–graphene oxide composite hydrogels by multi-modulus components strategy as photothermal antibacterial platform

Biomacromolecule-derived hydrogels have gained increased attention owing to their favorable hydrophilicity, flexibility, biocompatibility, and biodegradability. However, enhancing the mechanical strength of these hydrogels, while simultaneously improving their toughness remains a challenging task. Herein, a strategy of using multi-modulus components is proposed to fabricate strong and tough cellulose–graphene oxide (GO) composite hydrogels. The GO nanosheet content, molar ratio of the GO crosslinker to anhydroglucose units of cellulose, and ethanol concentration are shown to be critical parameters for achieving cellulose–GO nanosheet composite hydrogels with high strength and high toughness; the highest stress and work of fracture of the as-prepared composite hydrogels reached 13.6 MPa and 1.47 MJ/m3, respectively, in the compressive mode, and 2.8 MPa and 1.40 MJ/m3, respectively, in the tensile mode. The strengthening and toughening mechanism of the hydrogels composed of multi-modulus components is discussed. Moreover, the composite hydrogels exhibited excellent photothermal antibacterial properties against Escherichia coli and Staphylococcus aureus under near-infrared irradiation. We anticipate that the strategy of using multi-modulus components will inspire new design principles toward the development of high-strength and high-toughness biomacromolecule-derived hydrogels for biomedical devices, flexible bioelectronics, and others.