Preparation And Research Of Polyanilinel/Transition Metal Ion Hybrid Electrochromic Materials Based On Coordination Bonds

With the rapid development of social economy and the continuous improvement of people’s living standards,people not only pursue material life,but also pay great attention to the green and environmental lifestyle.The emergence of electrochromic devices can improve the energy waste caused by the increase of glass curtain walls in buildings.It is a new kind of green environmental protection material.Polyaniline is a potential electrochromic material with high optical contrast,low conductivity and shorter switching time.In order to further improve the properties of polyaniline,we intend to compound polyaniline with transition metal ions to prepare polyaniline/transition metal ion hybrid electrochromic materials based on coordination bonds.In this study,the water-soluble ferrocene/polyaniline hybrid electrochromic materials with coordination bond and covalent bond were synthesized by copolymerization of acetylferrocene with aniline.Secondly,the organic ligand(terpyridine)was used as a side chain to the polyaniline molecular chain to synthesize a terpyridine/polyaniline water-soluble hybrid electrochromic material with a side chain.Then the tripyridine/polyaniline hybrid material was coordinated with transition metal ions(M=Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ))to successfully synthesize the water-soluble hybrid electrochromic material with transition metal ions(M=Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ)).Through a series of morphological characterization and electrochromic and electrochemical performance tests,the following experimental results were obtained:(1)Firstly,ferrocene with aniline group was reacted with aniline by chemical oxidation to synthesize water-soluble ferrocene/polyaniline hybrid electrochromic materials.The experimental results show that ferrocene as an electroactive group,has a good reversible redox reaction,redox activity and good stability,this makes the maximum optical contrast of ferrocene/polyaniline electrochromic devices 49%higher than that of polyaniline.And the colouring time also decreases because the doped modified Fe2+ in the cyclopentadienyl center of ferrocene is a good electron transport medium,which can significantly enhance the electrochemical performance of the material,improve the electron dispersion and thus increase the electron transfer rate in the system.Therefore,when the material is applied with a positive voltage,the oxidation reaction is more likely to occur and the electrons are lost,thereby shortening the coloring time of the material.(2)The modified tripyridine was grafted onto polyaniline molecular chains in the form of side chains,and water-soluble hybrid electrochromic materials of tripyridine/polyaniline with side chains were successfully synthesized.The experimental results show that when 10%tripyridine is grafted onto the polyaniline molecular chain,the maximum contrast is increased by 51%,and the electrochemical activity is also enhanced.The polyaniline hybrid electrochromic material doped with 10%terpyridine/polyaniline was coordinated with a transition metal ion to successfully synthesize a terpyridine/polyaniline/transition metal ion(Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ))water-soluble hybrid electrochromic materials.The results show that,compared with polyaniline,the hybrid material coordinated with Fe(Ⅱ)has a contrast improvement of about 76%,coordination with Co(Ⅱ)is increased by nearly 73%;and coordination with Ni(Ⅱ)is also 54%increase.