Large deformable multiwalled carbon nanotube core-shell structure on polystyrene beads

Multiwalled carbon nanotube (MWCNT)-coated polystyrene (PS) beads have been prepared by dispersion polymerization followed by a layer-by-layer self-assembly method. The concentration of carboxylic acid groups on the MWCNTs increased from 1.81 × 10²¹ to 3.43 × 10²² COO^- per g as the treatment time was increased from 3 to 9 h. The sulfonated polystyrene (SPS) beads changed from being negatively charged to positively charged when the cationic polyelectrolyte was self-assembled on their surface. The surface morphology of the adsorbed polyelectrolyte was smooth without any aggregation and the thickness of the polyelectrolyte coating on the SPS beads was ≈0.6 μm. The electrical conductivity and resistance of the MWCNT-coated SPS beads were measured to be 4.0 × 10^-2 S · cm^-1 and 12.8 Ω at a volume fraction of 91%, respectively.