Study On The Emulsion Polymerization Of Poly3,4-ethylenedioxythiophene (PEDOT) And Its Properties

Conductive polymers have very important potential applications in the electrode materials,anti-static coating portable energy display device due to their unique properties. Compared withthe conducting polymer polypyrrole(PPY), polyaniline(PANI) etc, polythiophene(PTH) and itsderivatives have better environment stability, simpler preparation process, higher electricalconductivity after doped, leading to a more wide range of purposes. PEDOT was studied as theresearch object in this paper. A series PEDOT emuls ion were prepared through emulsificationpolymerization. The stability and film-forming conductivity of the PEDOT emulsion were studied,hoping to get the nano PEDOT emulsion with good conductive and good stability.In this paper, the poly(sodium-p-styrenesulfonate)(PSSNa) was used as surfactant and dopingagent, FeCl36H2O(or iron(III) p-Toluenesulfonate(Fe(OTs)3)) was used as the oxidant andcatalyst, K2S2O8was used as the oxidant. Influences of the emulsification conditions such as theamount of catalyst, oxidant, doping agent etc were studied. Results were obtained as the follows:the emulsion stirring speed has little effect to the conductive properties and stability of the PEDOTemulsion, but high stirring speed could result in smaller particle size of PEDOT emulsion; Thecatalyst amount has a significant impact on the emulsion stability and the reaction, the reactionproceeds very slowly when the amount of catalyst is too low, while the stability will reduce withexcessive amount of catalyst; The amount of PSSNa have a certain influence on the stability andconductivity of emulsion. Reduce the PSSNa amount will increase the film conductivity of theemulsions, while reduce the centrifugal stability at the same time. Using small molecules such ascamphor sulfonic acid and amino acid as the co-doping agent can improve the conductivity of theemulsion, but reduce the centrifugal stability. Organic solvents could reduce the particle size ofsynthetized PEDOT emulsions to less than50nm, but the corresponding films show no conductiveproperties. The conductive properties of the emulsion was found to be improved to a certain extantvia double emuls ification process, but the obtained emulsions show poor stability.