Preparation And Properties Study Of The Self-healing Electrochromic Materials

Owing to the aging,mechanical damage or the ions reversibly insertion/extraction,the generation of crack would result in performance degradation of the electrochromic materials or devices during the usage process.Inspired by injury organism can be automatically healing wound,the self-healing function groups were introduced into the electrochromic materials to obtain the self-healing electrochromic materials.It is expected that the self-healing electrochromic materials can quickly and effectively repair the crack or damage without any affection for the electrochromic performance,electrochromic device.The electrochemistry kinetics and self-healing performance of the films were studied,the redox mechanism and colors switching behavior was expounded,and the independent enhancement mechanism between of the self-healing and electrochroism were verified,which solve the crack or damage problem and improve the service life and reliability,the research contents are as follows:?1?The triphenylamine?TPA?as the electrochromic group,the furan and maleic imide as the self-healing groups to crosslinking polymerize the DATPFMA polymer materials.The triphenylamine functional groups maintain excellent performance,the results show that the DATPFMA film has electrochromic and self-healing function:the DATPFMA film under different voltage can switch colors from light yellow?0 V?to green?0.45 V?and deep blue?0.7 V?.The coloration efficiency at 580 and 1060 nm were 82.2,175.3 cm²C^-1,respectively.The coloration and bleaching response time were4.1 and 11.0 s,respectively.Under the condition of 110^oC,the crack of the DATPFMA film can be self-healed within 5 min which was observed by the mobile microscope,the self-healing efficiency is high as 80%.The electrochromic performance has no obvious change before and after self-healing.?2?On the implementation basis of electrochromic and self-healing function,the triphenylamine group was substituted by the N',N'-bis?4-aminophenyl?-N,N'diphenyl-1,4-phenylenediamine group to increas the number of electrochromic color center.The target self-healing electrochromic DAPPFMA film was prepared.The electrochemistry and charger transfer behavior was studied,and the the optical contrast regulation and cycle stability were improved.The colors can be changed from pale yellow?0 V?to grass green?0.85 V?and dark blue?1.15 V?,the optical contrast as high as 42.7%.The cycle stability was obviouly improved,the optical contrast only decreased 8.4%after100 cycles.At the same time,the DAPPFMA film is coated onto flexible ITO/PET electrode by blade coating,and then assembled the flexible electrochromic device,the device has good electrochromic and self-healing properties.?3?The polyimide structure is introduced to the self-healing electrochromic materials to enhance the mechanical properties,and a new flexible,stretchable,free-standing DFTPA-PI-MA film was obtained.The DFTPA-PI-MA film can switch colors from faint yellow?0 V?to olive green?1.1 V?,and have good cycle stability?optical contrast attenuation only 1.12%after 100 cycles?.The results show that the electrochromic performance of DFTPA-PI-MA film has no obvious change before and after self-healing,the coloration/bleaching response time before and after self-healing process were 5.3/12.2 and 4.9/12.2 s,respectively.The coloration efficiency at 905 nm before and after self-healing process were 82.8,73.8 cm²C^-1.The film crack repair completely within 3 minutes under 110 ^oC,and for the cut film can be self-healed back to tensile state,the self-healing efficiency is high as 90%.Finally,DFTPA-PI-MA material coated on the conductive silver fabric,and assembled the wearable bionic"chameleon skin",the device has excellent electrochromic and self-healing properties.?4?The self-healing and electrochromic materials TAFPy-MA based on pyrene was designed to avoid the multilayer interface barrier of the traditional devices,methyl viologen as complementary electrochromic material,with the integration of all solid state electrolyte to obtain the all-in-one self-healing electrochromic materials.The intermolecular forces of the methyl viologen and TAFPy-MA was confirmed by the electronic static potential and fluorescence lifetime decay,and the suitable energy gaps are highly consistent for smooth electron transfer to construct the in-situ redox reaction process,and enhance the electrochromic performance at the same time.The electrochemistry behaiovr were studied bu the electrochemical impedance spectroscopy,diffusion resistance simulation calculation and ion diffusion coefficient,and the electrochromic kinetics and ions extract/insert mechanism of the all-in-one electrochromic material was also studied.The crosslinking structure can self-heal the cracks of the electochromic films,to improve the reliability of the film or device.It's proved that the thin film device has high ionic mobility,coloration and bleaching response time are 3.7 and 3.9 s,respectively.The coloration efficiency is as high as 413cm²C^-1,the optical contrast can keep 88.7%after 1000 cycles.The self-healing speed significantly promoted,crack can be quickly self-healed within 110 s.Finally,the large-area electrochromic glass?30×35 cm²?was aslo prepared based on the all-in-one self-healing electrochromic material,the packaging and preparation technology of electrochromic devices were greatly simplify.In summary,to solve the crack generation of the traditional electrochromic materials or devices during the usage process,the self-healing electrochromic materials with excellent performance are designed and prepared in this thesis,and hopeful to improve the service life or reliability.