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We report the preparation and characterization of pure polyaniline nanoparticles (PANI_NPs), zinc oxide nanoparticles (ZnO_NPs), and ZnO_NPs/PANI hybrid inorganic/organic nanocomposites (HION) dispersed in aqueous sodium dodecyl sulfate solutions. We have characterized the HION, which were prepared by the polymerization of aniline in presence of sodium dodecyl sulfate and ZnO_NPs, by dynamic light scattering, zeta potential, Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). We have obtained ZnO_NPs, PANI_NPs, and ZnO_NPs/ PANI with negative values of zeta potential and average diameters of 4.6 nm, 3.6 nm and 8.1 nm, respectively. XRD results reveal that the polymer exhibits a well-defined crystalline phase, as well as the presence of ZnO in a hex-agonal phase. The observed changes in the FTIR spectra of the HION are associated to the formation of hydrogen bonding between the ZnO_NPs and the NAH groups present in the PANI chains. Heterogeneous structures with fibrous characteristics are identified in the SEM images. Electrical measurements indicate that the ZnO_NPs/PANI HION exhibit a noticeable light-sensitive ohmic behavior. We suggest that the preparation method here described offers an easy route of synthesis for the development of water-soluble ZnO/PANI-based nanostructures with high colloidal stability and varied functionality. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 125: E141-E147, 2012

We have prepared magnetite nanoparticles (Fe 3 O 4 _NPs) almost spherical in shape with average particle size of 10 nm and successfully encapsulated them in an envelope of polypyrrole (PPY) chains via an emulsion polymerization route using sodium dodecyl sulfate as surfactant. The resulting PPY-coated Fe 3 O 4 _NPs (Fe 3 O 4 _NPs/PPY) suspensions were stable with particles exhibiting a triangular prismatic morphology and an average diameter below 100 nm. In fact, all colloidal solutions were stable in aqueous media with typical f-surface potential values of À33.9 mV (Fe 3 O 4 _NPs) and À20.0 mV (Fe 3 O 4 _NPs/PPY). Although X-ray diffraction studies revealed the presence of a magnetic phase Fe 3 O 4 , the identified diffraction peaks are consistent with the presence of a spinel structure of magnetite. A ferromagnetic behavior, such as lower coercive force (H c ¼ 0.065 T), was observed for all magnetic nanoparticles examined. The 1 H NMR relaxation times T 1 and T 2 of selected Fe 3 O 4 _NPs/PPY samples were also measured and their relaxivities r 1 (1.1 s À1 mM À1 ) and r 2 (61.9 s À1 mM À1 ) compare favorably to those of contrast agents commercially used in human examinations. We suggest that the present results indicate that these hybrid nanocomposites are promising materials for the development of a platform of specialized contrast agents for 1 H Magnetic Resonance Imaging.

We synthesized (ZnO nanoparticles)/polypyrrole (ZnO_NPs/PPy) hybrid nanocomposites and used them as additives in an epoxy paint to protect SAE 1020 carbon steel from corrosion. The nanocomposites were obtained by chemical polymerization of pyrrole in aqueous solution and sodium dodecyl sulfate solution containing dispersed ZnO nanoparticles. We characterized the nanoparticles by infrared absorption spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A large disparity in the distribution of ZnO particle sizes became evident from the TEM images, which also show the formation of hybrid nanocomposites consisting of polypyrrole coated ZnO nanoparticles. Electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) tests, which were performed on SAE 1020 carbon steel plates coated with epoxy and ZnO_NPs/PPy, have shown that epoxy paints have their efficiency as anticorrosive coatings significantly improved when ZnO_NPs/PPy hybrid nanocomposites are added to them.