▎ 摘　　要

It is widely recognized that combining alginate with graphene oxide (GO) is an effective method in improving the properties of alginate fiber. However, how the lateral size of GO influences the properties of the composite fiber is still unclear. In this work, GO was separated into four kinds of different lateral sizes with the assistance of centrifugation and high-power ultrasound. The tensile strength of calcium alginate/graphene oxide (CaAlg/GO) composite fiber increased with the lateral size of GO. Surprisingly, the combination of large and small GO performed the superior reinforcement effect. The tensile strength and Young's modulus increased from 407.66 MPa and 13.87 GPa to 556.97 MPa and 20.57 GPa, respectively. In addition, the water absorption ability of CaAlg/GO composite fiber reduced with the decreasing of the lateral size of GO. With significantly improved mechanical properties and fine biocompatibility, the CaAlg/GO composite fibers may have potential applications in the biotechnological, biomedical, and tissue engineering areas.