Electrorheological properties of poly(acrylonitrile) microspheres coated with multiwall carbon nanotubes

Poly(acrylonitrile) (PAN) particles coated with functionalized multiwall carbon nanotubes (fMCNTs) were prepared and applied to electrorheological (ER) fluids. First, carboxylic acid groups were introduced on the multiwall carbon nanotubes by chemical oxidation method. Then, nitrile groups on the surface PAN particles were modified to amine groups by Co catalysis reaction. Finally, fMCNTs were anchored on the surface of polymer particles by covalent bonding between carboxylic acid groups on fMCNTs and amine groups on particles. fMCNTs attached polymeric microspheres were characterized by scanning electron microscopy and optical microscopy. The ER properties of fMCNTs modified microspheres were measured under controlled electric fields. Although the amount of fMCNTs anchored on the surfaces of microspheres was 1 wt.% of polymers, good ER properties were observed. This improvement may be caused by fMCNTs enhancing the electrical properties of polymer microspheres.