Sequential Admicellar Polymerization of Polyindole and Poly(vinyl Acetate) for Increasing Electrical Conductivity and Water Dispersion of Multiwalled Carbon Nanotubes

Polymeric coatings are known to enhance the processing and performance of multiwalled carbon nanotubes (MWCNTs) in composites. Sequential admicellar polymerization (s-AP) was applied to facilitate aqueous dispersion of MWCNTs and enhance their electrical conductivity for fillers in hydrophilic composites. The process involved double AP to create two functional polymer layers on the MWCNT surfaces. Initially, polyindole (PIn) was formed, followed by the formation of poly(vinyl acetate) (PVAc) as the second layer with thicknesses as thin as 3–4 nm for PIn and 5 nm for PVAc by FESEM image analysis. Optimal properties were achieved at 30 mM indole and 20 mM vinyl acetate monomer concentrations, yielding a 57% increase in electrical conductivity (8.23 × 104 S/cm) and a stable MWCNT suspension in water. HPLC was used to analyze and investigate the monomer adsorption inside admicelles of SDS on the MWCNT surface. FTIR, FESEM, and TGA were applied for further characterization.