Preparation of Hybrid Polyaniline/Nanoparticle Membranes for Water Treatment Using an Inverse Emulsion Polymerization Technique under Sonication

This manuscript describes a novel in situ interfacial dynamic inverse emulsion polymerization process under sonication of aniline in the presence of carbon nanotubes (CNT) and graphene nanoparticles in ethanol. This polymerization method is simple and very rapid (up to 10 min) compared to other techniques reported in the literature. During polymerization, the nanoparticles are coated with polyaniline (PANI), forming a core-shell structure, as confirmed by high-resolution scanning electron microscopy (HRSEM) and Fourier-Transform Infrared (FTIR) measurements. The membrane pore sizes range between 100–200 nm, with an average value of ~119 ± 28.3 nm. The film resistivity decreased when treated with alcohol, and this behavior was used for selection of the most efficient alcohol as a solvent for this polymerization technique. The membrane permeability of the PANI grafted CNT was lower than the CNT reference, thus demonstrating better membranal properties. As measured by water permeability, these are ultrafiltration membranes. An antimicrobial activity test showed that whereas the reference nanoparticle Bucky paper developed a large bacterial colony, the PANI grafted CNT sample had no bacterial activity. The thicker, 2.56 mm membranes exhibited high salt removal properties at a low pressure drop. Such active membranes comprise a novel approach for future water treatment applications.

Synthesis of Soluble and Highly Thermally Stable Polyaniline- Titanium Dioxide Composite via Inverse Emulsion Polymerization

Polyaniline (PANI)/Titanium dioxide (TiO2) composites were prepared by polymerization of aniline in the presence of TiO2 using inverse emulsion polymerization protocol. In this method 2-butanol and chloroform were used as dispersing media and the materials were tested for corrosion protection of stainless steel in Indian Ocean water. The amount of aniline, oxidant (Benzoyl peroxide), Dodecylbenzenesulphonic acid (DBSA) surfactant and metal oxide (TiO2) were varied in the reaction bath for optimum yield. The as-synthesized PANI and PANI-TiO2 composites were soluble in a number of common organic solvents and characterized with Ultravilot-visivble (UVand#172;-Vis) and Fourier Transform Infra-Red (FT-IR) spectroscopies. The surface morphology, particle size and crystinality were determined with Scanning Electron Microscopy (SEM) and X-Rays Diffraction (XRD) analysis. Thermogravimetric analysis (TGA) was employed to determine thermal stability of the composite. The total mass loss was found to be 58% in PANI as compared to 22% in PANI-TiO2 showing comparatively higher thermal stability of the composites. The composites were electrochemically active in acidic medium and reduced corrosion rate of steel to 0.9083 mm/ year Indian Ocean water. Finally it was concluded that PANI-TiO2 composites could be employed as anticorrosive coatings for steel in aggressive corrosive environment