GREGÓRIO JUNIOR, R.

MARTINEZ, R. A.

MATTOSO, L. H. C.

MEDEIROS, E. S.

UEKI, M. M.

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II\CAM2009\'. Abstracts~ ISSN 1983-7542-'::,-~'--s-..,.. .., .ICAM200911 til International Conferenceon Advanced MateriaisICAM2009Rio de Janeiro BrazilSeptember 20 - 25In situ synthesis of conducting polymer blends bya novel double interfacialpolymerization methodE.S. Medeiros(1,2),M. M. Ueki(2),R.A. Martinez(1,2), R. Gregório, Jr. (2),L. H. C. Mattoso'l'"(1) Embrapa Instrumentação Agropecuária, São Carlos-SP, Brazile-mail: mattoso@cnpdia.embrapa.br(2) UFSCar/DEMa, São Carlos, SP, BrazilAbstract - A nanostruetured blend of polyaniline (PAni) and polypyrrole (PPy) doped with eamphorsulphonie aeid (CSA) wasprodueed in situ by the simultaneous polymerization of aniline and pyrrole using a double interfaeial system whieh eomprises of treephases of mutually insoluble liquids with different densities, i.e., organie top phasel aqueous intermediate phase/organie bottom phase.The blend was SEM, UV-Vis and XRD. Charaeterization evideneed blend formation rather than eopolymerization, thus indieating thatthis method ean be sueeessfully applied to produee in situ blends of eondueting polymers.Copolymers and composites of conducting polymers can be chemically ar electrochemically preparedby (i) electropolymerization of two monomers in two steps; (ii) one step synthesis resulting in a copolymerrather than a polymer blend; (iii) alternate depositions of two conducting polymers using depositiontechniques such as self-assembly and spin coating; and (iv) mixing the conducting polymers (powder orsolution) prior to deposition [1-4]. However, polymers have to be mixed properly, which in many cases is adifficult, relatively expensive and time-consuming process, since inefficiently mixing can lead to anisotropicproperties and low performance blends. This work dealt with the development of a novel method to producein situ conducting polymer blends using a double interfacial polymerization system which comprises of treephases of mutually insoluble liquids with different densities, i.e., organic top phase/ aqueous intermediatephase/organic bottom phase (Fig.1 a) and their characterization by SEM, UV-Vis and XRD.Fig. 1a shows that both pyrrole and aniline monomers migrate toward the aqueous phase to form ablend as the two interfacial polymerizations take place simultaneously whereas polymers mix together.FESEM micrographs (Fig.1 b) show that the morphology obtained is a mixture of nanoparticles (polypyrrole)and nanofibers (polyaniline) rather than a blend. Moreover, UV-Vis spectra (Fig. 1c) corroborate theseresults showing that the spectrum of the composite comprises of characteristic absorptions of the individualpolymers. XRD patterns (Fig.1c) show that the simultaneous polymerization not only yields a blend with eachpolymer individual structure but also gives rise to new phases due to co-crystallization of PAni and PPymolecules during the synthesis. Although SEM micrographs have shown the existence of a morphologywhich is typical of each polymer rather than a single phase, at the lattice levei some polypyrrole andpolyaniline chains co-crystallized modifying the overall crystalline structure without any visible morphologicalchanges.In summary, conducting blends of polyaniline and polypyrrole were produced in situ by a simultaneouspolymerization of aniline and pyrrole using a double interfacial system and the characterization evidencedblend formation rather than copolymerization, indicating that this novel blending method can be successfullyapplied to produce in situ blends of conducting polymer nanostructures preserving both the individualmorphology and properties of each polymer.- ~polymc] nuxture-r=>:». ~ (d":;~t:~ca~i~i~<~ ~PAniPAny+ PPy(doubleinterfacial) \\J28 [degree]~~~~~~~\Na'lelef"l;th (nm)I , I900 100') 1100(a) (b) (e) (d)Figure 1: a) snapshot, b) SEM mierograph, c) XRD patters and d) UV-Vis speetra of the double polymerization system for thesynthesis of polyaniline and polypyrrole nanostruetures.References[1] 8, Sar and M. Talu, Synth. Me!. 94 (1998) 221-227[2] S. 8ereznev, I. Golovstov, A. Opik, Synth. Me!. 121 (2001) 1415-1416[3] R. Taipalus, T. Harmia, M. Q. Zhang, K. Friedrieh, Compo. Sei. Teeh. 61 (2001) 801-814[4] G. S. Akundy, R. Rajagopalan, J. O. Iroh, J. Appl. Polym. Sei. 83 (2002) 1970-1977

In situ synthesis of conducting polymer blends by a novel double interfacial polymerization method.

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