PEDOT-Sulfate Nanocrystalline Cellulose Composites and Their Characterization

Abstract

Some kinds of sulfated cellulose (CS) with various degrees of substitution of sulfate groups (DS) were prepared through direct sulfation of cellulose. PEDOT/CS were prepared via in situ chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) in aqueous solution of CS. The PEDOT/CS films were formed on glass substrates by spin-coating. The electrical conductivity of the PEDOT/CS film with a DS of 1.03 was 0.576 S cm⁻¹. Through TEM images of PEDOT/CS, the nanocrystalline morphology depending on CS was observed. Using X-ray diffraction, we studied the crystallinity of cellulose chains in the PEDOT/CS. The electrical conductivity of PEDOT/CS tended to increase with the crystallinity of the cellulose. Thus, EDOT molecules can polymerize and form a complex, lining up around the nanocrystalline cellulose. Using Raman spectroscopy, we studied the conformation of PEDOT chains in the PEDOT/CS and PEDOT/PSS films. We attributed the increased electrical conductivity of the PEDOT/CS film to an increase in the proportion of the quinoid structure in the PEDOT.