Preparation of PEDOT/PSSA conductive nanoparticles for dielectrophoretic display

Poly(3,4-ethylenedioxythiophene) (PEDOT):poly(styrene sulfonic acid) (PSSA) nanoparticles for dielectrophoretic display were prepared by in situ polymerization of 3,4-ethylenedioxythiophene in the PSSA nanoparticle, which was obtained from the sulfonation of polystyrene nanoparticles prepared by a conventional emulsion technique. The properties of the resulting nanoparticle were characterized by Fourier transform infrared spectrascopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the dynamic light scattering (DLS) technique. The particle was uniform in spherical shape with an average diameter of ca. 300∼320 nm, and showed high thermal stability up to 340 C. The electrical conductivity of the PEDOT:PSSA nanoparticle was measured to be as high as 0.11 S/cm. The dielectrophoretic display cell prepared from the colloidal PEDOT:PSSA nanoparticle dispersed in nematic liquid crystal showed significant optical change in response to electric field variation.