Enhancement Of Iron Complexes On The Electrical Response Properties Of Gelatin Hydrogels

The physical and chemical properties of the smart hydrogel can be changed when it was excited by the external stimuli.The external stimuli can be physical ones,such as light,electricity,magnetism,and thermo,or chemical one such as pH and ion concentration.Smart hydrogels that can respond to an external electric field which call electro-response hydrogels.For example,gelatin composed by natural polypeptide chains has good gelled properties and biocompatibility,and has certain electro-response properties.In order to improve the response performance of gelatin hydrogel to electric field,this paper used three ferric complexes with good solubility:sodium ferric ethylenediaminetetraacetate(EDTA-Fe),sodium ferric gluconate(SG-Fe)and ferric chitooligosaccharides(COS-Fe)were added into gelatin respectively,which not only improved the electrical response of gelatin,but also acted as a physical cross-linking agent to promote the cross-linking of gelatin polypeptide chains.Finally,three homogeneous,biocompatible EDTA-Fe/gelatin,SG-Fe/gelatin and COS-Fe/gelatin electro-response hydrogels were prepared.Among of them,the hydrogels prepared by the direct current electric field(E=0,0.4,0.8 kV/mm)was called A-hydrogel,and the hydrogels prepared without an electric field called B-hydrogel.In the research process,firstly,the structures of three ferric complexes were analyzed with UV-Vis spectrophotometer(UV-Vis),fourier infrared spectrometer(FT-IR),X-ray diffractometer(XRD)and thermogravimetric analyzer(TGA).Secondly,the mechanism of the interaction between each ferric complex and gelatin was analyzed by FT-IR.And the compressive storage modulus GA,GB of the composite hydrogels were obtained by dynamic viscoelastic spectrometer(DMA).On the basis of GA and GB,storage modulus enhancement(?G=GA-GB)and the storage modulus enhancement sensitivity(?G/GB)was introduced to reflect the electro-response of the gelatin more intuitively.Thirdly,the electro-response mechanism of three composite hydrogels to electric field was analyzed by scanning electron microscope(SEM)and TGA.The...