Conducting polymer composites of polystyrene and poly (3,4-ethylenedioxythiophene) prepared by electrospinning and heat-activated polymerization

Abstract

Conducting polymer composite films containing poly(3,4-ethylenedioxy thiophene) (PEDOT) was prepared by solid state polymerization (SSP) of 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) in the presence of polystyrene (PS) or sulfonated polystyrene (SPS) matrix. A thin fiber mat was first fabricated by electrospinning a solution mixture of polymer matrix (PS or SPS) and DBEDOT on glass slides. After the solvent was removed, the solid state polymerization of the DBEDOT crystals embedded in the polymer matrix was then induced by heating at 60-80 °C, the temperature below the glass transition temperature of the polymer matrix and the melting temperature of DBEDOT. A dark blue composite film containing PEDOT was then formed through debromination and coupling. It was found that compression during heating was necessary to produce well dispersed sub-micron PEDOT in the polymer matrix. As measured by four-point probe conductometer, the conductivity of the composite film can reach as high as 13.24 S/cm, the value equivalent to the conductivity of the pure PEDOT also generated by SSP in the absence of polymer matrix. The characteristics of the synthesized PEDOT were also determined by electron spin resonance spectrometry, fourier-transform raman spectrometry, x-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis.