Studies On The Preparation,Structures And Properties Of Self-healing Hydrogels

Self-healing hydrogels have the ability to restore their structures and properties after damage and have been applied in many fields,such as sealant and tissue engineering.Self-healing hydrogels achieve their self-healing properties through dynamic covalent bonds or reversible non-covalent bonds.The self-healing performance of hydrogels often requires external stimuli,namely,they can not repair themselves intrinsically and automatically,which limits their application.In this paper,we prepared the hydrogels by a complete physical cossing-linking method.They can spontaneously self-heal without any stimuli at room temperature.The structures and properties have been studied:（1）Dual physical crosslinked Laponite/PAA-Fe³⁺composite hydrogels have been formed by Laponite and Fe³⁺interacted with PAA chains.Experiments showed the hydrogels can achieve self-healing at room temperature.The compositions,structures and properties of composite hydrogels were characterized with SEM,FTIR,DSC,tensile tests and rheology measurements.The strength and self-healing properties of hydrogels with changing the content of Laponite and Fe³⁺were studied.The results showed that Laponite played a role in supporting shape and strengthening hydrogels.However,it can hidered the self-healing performance.While the introduction of Fe³⁺can greatly facilitate the self-healing properties.（2）Hydrophobic hydrogels were prepared by copolymerization of acrylamide（AM）with stearyl methacrylate（SMA）in a SDS–NaCl micelle system.The phenomenon of polarization interference induced mainly by mechanical deformation was studied.The structures,morphologies of hydrogels were characterized with SEM,POM,XRD,and so on.Their mechanical properties and self-healing properties were studied by tensile test.The results indicated that mixed micelles of SDS and hydrophobic blocks of the polymer could self-assemble to form a layered micelle structure.The layered micelle can be arranged in order by external mechanical effect,which leads to a polarization interference phenomenon.（3）On the basis of the previous work of our lab,we supplemented the study on the structures and properties of the composite films containing carbon nanotubes（CNTs）and cellulose nanocrystals（CNCs）formed by evaporation-induced arrangement.The assembly of CNTs in the chiral nematic liquid crystals（CNLCs）of CNCs was investigated.And the structure model of the CNC-CNTs composite films was put forward.