Preparation And Properties Of Rare Earth Metal Oxide Composite Polyaniline Electrochromic Films

Since the 21st century,the fossil energy crisis and greenhouse effect have become increasingly serious,which has greatly threatened the survival and development of human beings,and the research and development of energy-saving and emission-reducing technologies and materials has become the only way to ensure the sustainable development of economy,environment and energy.In terms of effective use of solar energy and energy saving,electrochromic materials and devices with reversible optical performance control functions have outstanding development needs.Firstly,the preparation of PANI electrochromic films by emulsion method and its influencing factors were studied,and the optimum synthesis conditions of PANI were determined.Based on this,lanthanum oxide（La₂O₃）and cerium dioxide（CeO₂）were modified by silane coupling agent.Then,the lanthanum oxide composite polyaniline（f-La₂O₃/PANI）and cerium oxide composite polyaniline（f-CeO₂/PANI）electrochromic materials were synthesized by in-situ polymerization.The effects of rare earth oxide content on molecular structure,aggregation structure,morphology and photoelectric properties of PANI were investigated.The following conclusions can be drawn from the above research:（1）The experimental results of influencing factors of PANI preparation by emulsion method showed that:The electrical conductivity and electrochemical activity of HCl doped PANI are generally higher than those of H₃BO₃ doped PANI but the thermal stability of HCl doped PANI is lower than that of H₃BO₃ doped PANI.The conductivity and electrochemical activity of PANI decrease with the increase of emulsifier content.When H/A=1:1 and the emulsifier content was 4%,the HCl-doped PANI had a Crosslinked network structure,the solubility reached 37.51%,the electrochemical activity was the highest,and the conductivity was the best,reaching 3.96 S/cm.（2）The results of the preparation and performance characterization of f-La₂O₃/PANI electrochromic films showed that:f-La₂O₃/PANI composites had higher crystallinity and thermal stability,and La₂O₃ can accelerate the transformation process of protonation and de protonation of PANI,and effectively inhibit the oxidative degradation of PANI in the process of film electrochromism.As the mol ratio of La₂O₃ to aniline was 1:3.5,the coloration efficiency is 22.81cm²·C^-1,and the fading and coloring response time（τ_b/τ_c）are 1.29 s and 1.33 s,respectively,after320 bleaching cycles,the electrochemical activity of the films remained about 50%of the initial value.（3）The results of the preparation and performance characterization of f-CeO₂/PANI electrochromic films showed that:f-CeO₂/PANI composites have higher crystallinity than pure PANI,and CeO₂ incorporation will affect the spectral absorption of PANI,when the molar percentage of CeO₂ is 20%,the composites show reversible changes of emerald green to dark green to reddish brown,and the electrochromic performance is the best,and the coloring efficiency at the wavelength of 570 nm is 1.56cm²·C^-1,coloring and fading time（τ_b/τ_c）were 12.3 s and 13.4 s,respectively,and the electrochemical activity of the film remained at about 40%after 320 fading cycles.Figure[50]Table[11]Reference[108]...