Study On Multifunctional Double-network Composite Hydrogels

Hydrogel,as a kind of flexible functional material,has always been a research hotspot in the academic field because of its three-dimensional hydrophilic network structure.Due to the great penetrability,hydrophilia and biocompatibility,it may be used in tissue engineering,drug delivery and so on.However,the application of the hydrogel is limited because of its weak mechanical property.Hence,researchers have developed many methods to enhance performance for extending its application.Double-network hydrogel combines two kinds of different networks to enhance its mechanical property.First,two networks were combined by two different monomers.Then they were gradually combined by chemistry and physical networks.The most common physical network was made by polyvinyl alcohol or polyethylene glycol,however,the biocompatibility and degradability of this polymer are poor.Therefore,natural polymer material,such as guar gum or carrageenan was used to replace it.Natural polymer material,as a kind of industrial raw material,has good degradability,and it is also a kind of environment-friendly material.Meanwhile,as a physical network,it can be compatible with another network to improve its mechanic property.In this paper,first,Fe₃O₄/MoS₂ was synthesized via hydrothermal method,then polyaniline?PAni?was added to the surface of Fe₃O₄/MoS₂,and Fe₃O₄/MoS₂/PAni ternary composites were prepared via in-situ chemical polymerization.Thereafter,the ternary composites were embedded into the robust double-network hydrogel consisted of acrylamide and guar gum,and a multifunctional double-network Fe₃O₄/MoS₂/PAni composite hydrogels with magnetic property and electric conductivity were prepared.The structure and properties of Fe₃O₄/MoS₂/PAni composite hydrogels were characterized by XRD,FITR,SEM,TEM,four-probe detector,vibrating sample magnetometer,thermogravimetric analysis and tensile tests.Meanwhile,the effect of the content of Fe3O4/MoS2/PAni ternary composites on the thermo-stability,mechanical property,swelling property,conductivity,magnetic performance of the composite hydrogels was studied.The experimental results showed that Fe₃O₄/MoS₂/PAni ternary composites not only endowed conductive and magnetic properties to hydrogel but also provided hydrogen bonds with molecular chain to obtain tough Fe₃O₄/MoS₂/PAni composite hydrogels.The maximum saturation magnetization and conductivity of the Fe₃O₄/MoS₂/PAni composite hydrogels were 1.28 emu·g^-1 and 2.052×10^-3S·cm^-1,respectively,and the tensile strength is 140 k Pa.In addition,Fe₃O₄ particle was modified by phosphoric acid 2-hydroxyethyl methacrylate ester?PHME?to obtain the modified Fe₃O₄ particle.Then,the modified Fe₃O₄ particle was introduced into double-network hydrogels composed of acrylamide,hydroxyethyl methyl acrylate and k-carrageenan through covalent bond,and a kind of modified Fe₃O₄ particle composite hydrogel was prepared.The modified Fe₃O₄ particle was characterized by FITR,XRD,TGA,XPS and EDS,and it was proved that Fe₃O₄ particle was modified successfully.The effect of the modified Fe₃O₄ on the performance of the composite hydrogel was investigated.The results indicated that the maximal swelling ratio of modified Fe₃O₄particle composite hydrogel was about 10.And the swelling ratio decreased when the modified Fe₃O₄particle was introduced.It was proved that the crosslinking density of composite hydrogel was improved by the modified Fe₃O₄ particle.Besides,the modified Fe₃O₄ particle enhanced the mechanical property and endowed magnetic property to composite hydrogel.The tensile strength and the maximum saturation magnetization of modified Fe₃O₄ particle composite hydrogel were 0.21 MPa and 1.5 emu·g^-1,respectively.It was proved that the method of modified particle and embedding the modified Fe₃O₄ particle into the hydrogel network through covalent bond was feasible.And the modified Fe₃O₄ particle composite hydrogel will have vast market potential and development prospect.