Conducting polyaniline nanoparticles encapsulated with polyacrylate via emulsifier free seeded emulsion polymerization

Abstract

Polyaniline/partially phosphorylated poly(vinyl alcohol)/polyacrylate (PAn/P-PVA)/PAc nanoparticles were synthesized by encapsulation of PAn/P-PVA nanoparticles with PAc via the emulsifier-free seeded emulsion polymerization. The (PAn/P-PVA)/PAc nanoparticles were prepared by varying acrylate amounts. The results showed that the maximum monomer conversion was 93.9% at appropriate loading of (PAn/P-PVA) nanoparticles and acrylate monomers. From X-ray diffraction analysis, the results showed that PAc were intercalated between the PAn/P-PVA layer. Fourier-transform infrared spectroscopy (FT-IR) spectra of (PAn/P-PVA)/PAc showed the functional groups of hydroxyl (-OH), carboxyl (C=O), phosphodiester (P=O) and benzenoid ring. The nanoparticles morphology were observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The spherical PAn/P-PVA agglomerates were coated with PAc. From thermogravimetric analysis, stability of (PAn/P-PVA)/PAc nanoparticles was decreased with increasing acrylate amount. For electrochemical aspect, the (PAn/P-PVA)/PAc coated on carbon fiber electrode was subjected to cyclic voltammetry (CV). The PAn/P-PVA nanoparticles were encapsulated sufficiently by the non-conductive PAc and it was found that as the acrylate amount increased, the peak current observed during CV decreased. From corrosion study in 1.0 M sulfuric acid solution, steel coated with (PAn/P-PVA)/PAc-8c nanocomposites showed the best corrosion resistance (CR) of 11.4%. The increase in the acrylate amount in nanocomposites improve the anticorrosive properties due to an increasing tortuosity of diffusion pathway of corrosion agents.