Preparation and characterization of polyvinyl alcohol/ sodium alginate/carboxymethyl cellulose composite hydrogels with oriented structure

In order to control complex motion behavior in organisms, most biological tissues have highly oriented structures and anisotropic mechanical properties, such as articular cartilage, muscle, skin and blood vessel. In this study, inspired by the directional structure and excellent mechanical properties of biological soft tissues, polyvinyl alcohol/carboxymethyl cellulose hydrogels with different contents of sodium alginate were prepared by combining freeze-thaw and prestretching methods. Compared with SEM images without pre-stretch hydrogels, there are obvious ordered pore structures in the pre-stretch samples along the tensile direction, and the network structure becomes denser. XRD and FTI R results indicate that the introduction of SA and CMC increases the number of internal hydrogen bond and forms new covalent bonds. The tensile strength of the hydrogel without annealing and stretching treatments is only 0.41MPa. After annealing and stretching treatments, the tensile strength of the hydrogel is increased to 0.93MPa. Furthermore, the creep deformation of hydrogel was reduced from 1.08 mm to 0.27 mm by annealing and stretching treatments. To sum up, these results suggested that PVA/SA/CMC composite hydrogels with oriented structure might have potential applications in soft tissue repair and other biomaterials.