Preparation of carbon nanotubes-incorporated polymeric microspheres for electrorheological fluids

Electrically conducting polymeric microspheres having an average diameter of similar to 92 mu m were prepared from composites of multiwalled carbon nanotubes (MWCNTs) and suspension-polymerized poly(vinyl chloride) (PVC) particles. Cetyl trimethylammonium bromide and sodium dodecylbenzene sulfonate were selected as the surfactants to stably disperse the MWCNTs in water. Strong adhesion of MWCNTs on file surfaces of the PVC microspheres was observed from the images obtained by field emission scanning electron microscopy. The amount of MWCNTs adsorbed oil the microspheres was approximately 2 wt.%, determined by thermogravimetric analysis. The electrical conductivity of these composite-microsphere was remarkably increased upto 1.5 x 10(-4) S/cm compared with that of the pure PVC microspheres (less than 10(-14) S/cm). because of the electrically conducting MWCNTs on their Surfaces. These microsphere also showed an electrorheological (ER) effect under an electric field (1.8 kV/mm) owing to the interfacial polarization of the MWCNTs-adsorbed microspheres, when they were dispersed in silicone oil (20 wt.%). The MWCNT-adsorbed PVC microspheres Formed linear Structures by electric force; i.e. the individual microspheres were connected to neighboring microspheres. (C) 2007 Elsevier B.V. All rights reserved.