Preparation And Study Of Mussel-inspired Hydrogels With Self-repairing And High Mechanical Properties

Hydrogel materials with dynamic mechanical properties,such as self-healing and self-recovery behavior,have been widely used in tissue engineering and bioengineering.Therefore,the research about self-healing hydrogel has become hotspot,recently.However,the mechanical behavior and rheological behavior of hydrogels usually conflicted with self-healing performance,which makes the researchers can only choose one between mechanical properties and self-healing property.Thus,developing the self-healing properties and excellent mechanical behavior of hydrogel material has become the most urgent breakthrough in the field of research.Aquatic mussels could attach to different surface relying on dopamine(Dopa)which provides strong adhesion to a variety of surface.The Dopa-based hydrogels have excellent self-healing ability due to strong complexation between phenolic hydroxyl groups of catechol and Fe3+ ions.However,these hydrogels are difficult to be applied to practice due to poor mechanical properties.Inspired by mussels,we introduced different energy dissipation mechanisms into the Dopa-based hydrogel network to significantly improve its mechanical properties.And the hydrogel could maintain theoriginal dopamine properties at the same time.Firstly,we present a simple and mussel-inspired strategy to prepare hydrogels with self-repairing and high mechanical properties.The catechol-Fe3+ chelation and hydrophobic associations were employed as dual physical crosslinking points,which played a critical role in the self-repairing behavior.Moreover,the hydrophobic association effect was additionally responsible for enhancing mechanical strength due to effective energy dissipation.As a result,the dopamine-functional hydrophobic association hydrogels could repair themselves in a short duration of less than 10 min,and own a mechanical strength of 30 kPa and high extensibility of 2000%.Furthermore,the self-repairing behavior was responsive to pH and temperature.Besides,the peeling adhesive strength of the hydrogels can reach 70 N m-1.Secondly,we prepared a Dopa-based hybrid double-network hydrogel.Agar was used as the first network and polyacrylamide(PAAm)was used as the second network.The first network is cross-linked by hydrogen bond of agar network.As for the second network,we use Dopa-Fe3+ as the physical crosslinking points,and N,N'-methylenebisacrylamide(MBA)as the chemical crosslinker.Under stress,the agar network would be firstly broken to dissipate energy.Meanwhile,the reversible cross-linking points of the second network would undergo the process of destroying-reformation.The chemical cross-linking pointsshould support the overall network of hydrogels.The Agar/PAAm-Dopa-Fe3+ DN hydrogel possesses self-healing properties and self-healing properties.Under 85% strain,the compressive stress can reach 2.5 MPa.We envision that the biomimetic hydrogels with self-repairing and high mechanical properties would widen their applications in the field of biomedical or industrial engineering.