Facile and green method for polystyrene grafted multi-walled carbon nanotubes and their electroresponse

Polystyrene (PS) microspheres with a mean diameter of 69 nm were prepared by emulsion polymerization. The PS microspheres were successfully decorated to multi-walled carbon nanotubes (MWNTs) induced by benzoyl peroxide in water during a high temperature refluxing process under nitrogen atmosphere. The as-prepared multi-walled carbon nanotube/polystyrene (MWNT/PS) nanocomposites were characterized by FTIR spectroscopy, Raman spectroscopy, SEM, TEM, differential scanning calorimetry (DSC), and electrical resistance measurements. The results reveal that PS microspheres are mainly covalently grafted onto the walls of MWNTs. The PS-decorated MWNTs show high solubility in toluene and xylene without sedimentation after 24 h. With MWNTs in the hybrids, PS achieved a considerable increase in electrical conductivity and glass-transition temperature (Tg). In particular, the obtained MWNT/PS composites were examined for electrorheological (ER) fluids, which showed thin and dense chains of particles after the application of an electric field. The facile and environmentally friendly technique presented in the present study could be an effective and promising method for the functionalization of MWNTs by other polymers.