Preparation And Performance Of Nanostructural Polyaniline And Polyaniline/TiO₂Composites

PANI/TiO₂nanocomposites combines the advantages of semiconductor, conductivepolymer and nano materials, some special properties maybe represent due to the coupling ofPANI/TiO₂.Therefore, the PANI/TiO₂nanocomposite research has become a hot research atabroad. This paper mainly aims at the synthesis, characterization and performance ofnanostructural PANI and PANI/TiO₂composites, the main research as follows:1. Utilizing the interface between HCl and CCl4, PANI nanofibers were prepared byinterfacial polymerization with compound oxidant of （NH₄）₂S₂O₈and K₂Cr₂O₇. Theinfluences of the （NH₄）₂S₂O₈/（K₂Cr₂O₇） ratio, concentration of aniline, the reaction time andtempreture on the PANI morphology,conductivity and yield were studied.The preparedsamples were characterized by TEM, FT-IR,XRD,DSC and US-vis spectra, respectively. Theresults show that with using the compound oxidant of90mol%（NH₄）₂S₂O₈and10mol%K₂Cr₂O₇and0.1M aniline solution at5℃,after8h,theregular morphology of PANInanofibers was obtained,the conductivity and yield of PANI is1.89S/cm,49.03%,respectively.2. With90mol%（NH₄）₂S₂O₈and10mol%K₂Cr₂O₇as the compound oxidant and surfaceactive agent （SAA） as soft template, high conductive PANI was synthesized by self-stabilizingdispersion polymerization （SSDP）. The influences of the different types surface active agent（SAA） on the morphologies and properties of PANI were investigated.The results show thatthe morphology of sample is nanofibers with adding anionic surfactant （DBSA）, with addingnon-ionic surfactant （PEG400） and cationic surfactant（TEA）, the morphology of sample isfan-shaped arborization and membrane，respectively. In addition, with adding surfactants,there are varying degrees of increase on the conductivity and yield of PANI, in which thehighest conductivity with adding DBSA is8.7S·cm^-1and the highest yield with addingPEG400is78.3%.3. By adding different molecule mass polyethyleneglycol （PEG） and changing theconcentration of the PEG, PANI nanotubes were synthesized by interfacial polymerization. Itwas found that the formation morphology and the size of the nanotubes were affected by therelative molecule mass of PEG and its concentration. When1.0wt.%PEG2000was used,uniform and long PANI nanotubes, which have near40nm in outer diameter,30nm in innerdiameter and1.0to2.0μm in length, were obtained, The formation of the PANI nanotubes is mainly due to the interfacial diffusion and the template of the hollow micellar. In addition,there are effect on the PANI conductivity and yield by the relative molecule mass of PEG andits concentration. the highest conductivity with adding PEG2000is2.38S·cm^-1and the highestyield with adding PEG6000is59.35%.4. PANI/TiO₂nanocomposites was synthesized by SSDP. the morphology and structureof PANI/TiO₂were characterized, the influences of the ratio of aniline and TiO₂on theconductivity, visible liaght absorption and photocatalytic activity of PANI/TiO₂nanocomposites were also investigated.when the molar ratio of aniline and TiO₂is1:80,PANI/TiO₂composite particles exhibiting uniform directional reticular structure, wherethe TiO₂particles are wrapped by PANI, the diameter of the TiO₂particle is about20nm, whilethe thickness of the outer layer of PANI between5to10nm;the photocatalytic activity of thePANI/TiO₂show the best, the degradation ratio of methyl orange irradiated for120min underthe sun light （AM1.5） reaches95%.