| Poly(3,4-ethylenedioxythiophene)(PEDOT) is a π-conjugated polymer and can exhibits high electrical conductivity, optical transparency and environmental stability. It is expected that PEDOT has a variety of applications, especially for flexible display devices, super capacitors, optoelectronic devices, electromagnetic shielding and electrochromic devices. Unfortunately, the conjugated backbone of PEDOT causes insoluble and infusible problem, which leads to the material rather intractable; hence, the commercial applications of PEDOT are limited. How to fabricate high quality PEDOT film has attacked many attentions. In this gtoup, conducting PEDOT coating on PI film was synthesized by liquid phase depositional polymerization. PI films were first dipped in Fe Cl3 solution and then suspended in EDOT solution. The adsorbed Fe Cl3 stimulated the oxidative polymerization of EDOT on PI surface. Obviously, the adsorption of Fe Cl3 and EDOT solvents are the key to liquid phase depositional polymerization.In this thesis, the effect of Fe Cl3 solvents on Fe Cl3 adsorbed on PI film and EDOT solvents on liquid phase depositional polymerization were studied. Peroxidized PI films were dippeed in Fe Cl3 solutions with different solvents. The adsorption of Fe Cl3 and the total amount of oxidants were measured by Spectrophotometric and Iodometry method respectively. The morphology of absorbed Fe Cl3 were imaged under SEM; the effect of Fe Cl3 solvents on the adsorption of Fe Cl3 and synthesized PEDOT coating was investigated. Then, EDOT solutions with different solvents were used for depositional polymerization. The solvation to Fe Cl3 and EDOT were analyzed with UV-vis; the sheet resistance of resultant PEDOT coating were measured with four-point probe meter; the conjugated chain of synthesized PEDOT were investigated with ATR-FTIR and Raman spectrometer; the doping level of the synthesized PEDOT films were determined with UV-Vis-NIR and XPS; the surface morphology and conductivity were revealed by SEM and C-AFM respectively; the effect of EDOT solvents on depositional polymerization was studied. Finally, PEDOT/PI film was connected to power supply as cathode and electroplated copper in electrolytic cell with acid electrolytic solution. The feasibility to fabricate adhesive-free FCCL was studied.After H2O2 immerssion, about 2 mmol/m2 of peroxide were introduced to PI surface. From Fe Cl3 solution, peroxidized PI could adsorb Fe Cl3; the greater the solubility of the solvents and the higher the viscosity, the adsorption of the total oxidants will be higher. Fe Cl3 would catalyze the decomposition of peroxide groups, reduced the total amount of oxidants, the total adsorbed oxidant range from 3~8 mmol/m2. High polar solvents tend to form uniform Fe Cl3 coating and result in PEDOT films with low sheet resistance. With ethanol as solvent for Fe Cl3, a uniform thin Fe Cl3 layer could cover PI surface.As PI films with adsorbed Fe Cl3 were suspended in EDOT solution with n-Heptane, cyclohexane, chloroform or toluene as solvent, the adsorbed Fe Cl3 could stimulate the oxidative polymerization of EDOT on PI surface in all the solutions and result in conducting PEDOT coating. But, the coating from toluene solution exhibited the highest conductivity; the sheet resistance was 400 ?. ATR-FTIR and Raman spectra indicated that the order of conjugated length for the PEDOT synthesized in the above solvents is: chloroform >toluene > cyclohexane > n-Heptane, consistent with the solvation ability of the solvent to Fe Cl3 and EDOT; XPS analysis reflected that the doping level of the synthesized PEDOT has the same tendency as conjugated length. SEM and C-AFM revealed that the deposited PEDOT coatings were continuous conductive film; with increasing pority of solvents, the roughness of the PEDOT coating decreased; whereas the adhesion increased.Copper foil could be deposited on the surface of PEDOT/PI film by electrical plating in acid copper plating solution, but the peel strength is 22N/m only. As copper chloride was adopted as secondary oxidant, nano copper particles could generate in synthesized PEDOT coating and the peel strength of deposited copper foil could be enhanced to 83 N/m. |
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