title: Bioinspired fully physically cross-linked double network hydrogels with a robust, tough and self-healing structure.
abstract: The conventional covalently cross-linked double network (DN) hydrogels with high stiffness often show low toughness and self-healing property due to the irreversible bond breakages in their networks. Therefore, scarcity of hydrogels that possess simultaneous features of stiffness, toughness, and autonomous self-healing properties at the same time remains a great challenge and seriously limits their biomedical applications. While, many natural materials acquire these features from their dynamic sacrificial bonds. Inspired by biomaterials, herein we propose a novel strategy to design stiff, tough and self-healing DN gels by substitution of both covalently cross-linked networks with strong, dynamic hydrogen bond cross-linked networks. The prepared fully physically cross-linked DN gels composed of strong agar biopolymer gel as the first network and tough polyvinyl alcohol (PVA) biopolymer gel as the second network. The DN gels demonstrated multiple-energy dissipating mechanisms with a high modulus up to 2200kPa, toughness up to 2111kJm-3, and ability to self-heal quickly and autonomously with regaining 67% of original strength only after 10min. The developed DN gels will open a new avenue to hydrogel research and holds high potential for diverse biomedical applications, such as scaffold, cartilage, tendon and muscle.
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, University of Maragheh, Maragheh 55181-83111, Iran. Electronic address: m.sabzi@maragheh.ac.ir.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sabzi
authors.affiliation: Department of Materials Engineering, Faculty of Engineering, University of Maragheh, Maragheh 55181-83111, Iran.
authors.forename: Navid
authors.initials: N
authors.lastname: Samadi
authors.affiliation: Institute of Polymeric Materials, Sahand University of Technology, Tabriz 55181-83111, Iran.
authors.forename: Farhang
authors.initials: F
authors.lastname: Abbasi
authors.affiliation: Department of Chemistry, Faculty of Science, University of Maragheh, Maragheh 55181-83111, Iran.
authors.forename: Gholam Reza
authors.initials: GR
authors.lastname: Mahdavinia
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, University of Maragheh, Maragheh 55181-83111, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Babaahmadi
mesh_terms: D000362:Agar / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D055119:Elastic Modulus; D020100:Hydrogels / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011142:Polyvinyl Alcohol / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D000362:Agar; D011142:Polyvinyl Alcohol
keywords: Agar biopolymer; Double network; Elastic modulus; Hydrogel; Physically cross-linked; Polyvinyl alcohol (PVA); Self-healing; Toughness