Electrochromic Properties Of Triphenylamine-contained Polysiloxane Flims

Electrochromic polymers have several advantages including outstanding coloration efficiency,fast switching ability,multiple colors with the same material,and fine-tuning of the band gap?and the color?through chemical structure modification.But they have some inherent drawbacks,such as lack of film uniformity over large surface,low material recovery and stability to environments which limit their application and investigation.In this dissertation,a series of work has been done with triphenylamine?TPA?used as electrochromic functional group.TPA groups have been introduced into the polymer backbone to modify the solubility which is benefit for the processability and application.The onset potentials,solubility,thermal stability,electrochromic properties and fluorescent properties of the polymers are optimized by introducing different substituents at the para position of TPA.A series of TPA-contained polyurethanes and epoxy resins are obtained by introducing TPA with different electron-withdrawing of conjunction groups substituted into the backbones of polyurethanes and epoxy resins.All of the polyurethanes and epoxy resins are soluble in most of the organic solvents.The solubility of the epoxy resins are better than that of the polyurethanes.The coloring times of the epoxy resins are between 2-4s,and the bleaching times are between 3-5s.The data of coloration efficiency are 48,28,191,97 and 220cm²C^-1,respectively.The coloring times of the polyurethanes are between 2-4s,and the bleaching times are between 2-5s.The data of coloration efficiency are 67,107,12,159 and 230cm²C^-1,respectively.A novel series of triphenylamine?TPA?-contained polysiloxanes?PTPASi?have been synthesized by a normal reaction of hydrosilylation through poly?methylhydrosiloxane??PMHS?with four TPA-based alkenes?TPAA?.With the incorporation of the polysiloxane backbones,all of the polysiloxanes display hydrophobicity since the contact angles of them are bigger than 90.At the same time,the polysiloxanes have better adhersion with the ITO conductive glasses.The four polymer films display nearly colorless in their natural state and three primary colors of red,green and blue in their oxidized state.The coloring times of the polysiloxanes are between 2-4s,and the bleaching times are between 2-5s.The data of coloration efficiency are 192,159,107 and 129cm²C^-1,respectively.The potential switching properties at high temperature of 150? have been investigated which show high stability and could be applied at a relatively high temperature and/or long term cycle switching.A novel triphenylamine?TPA?-contained polysiloxane?PTPASi?named P?PT-TB-TPA?Si has been synthesized through hydrosilylation method by one pot reaction of poly?methylhydrosiloxane??PMHS?with two different TPA-based alkenes?TPAA?simultaneously.The color of the polymer changed from colorless to red then to deep purple.The coloring time of the P?PT-TB-TPA?Si is 4.48 s,and the bleaching time is 3.05 s at 753 nm.The colration efficiency is 137cm²C^-1.In addition,the potential switching property of the P?PT-TB-TPA?Si at the temperature of 150? has been investigated.The high thermal stability makes the polymer potential for relatively high temperature and/or long term cycling application.A novel triphenylamine?TPA?-contained polysiloxane?PTPASi?named P?PT-FL-TPA?Si has been synthesized by introducing electrochromic functional group TPA and fluorescent functional group fluorenyl group.The polymer has both electrochromic and electrofluorochromic properties.The fluoersent spectra at different potentials reveal that with the increasing of potential the fluoersence was quenched.Otherwise,with the voltage increased,the color of the polymer changed from colorless to orange.The coloring time of the P?PT-FL-TPA?Si is 1.25 s,and the bleaching time is 1.04 s at 753 nm.The colration efficiency is 205cm²C^-1.