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This article describes chemically modified polyaniline and graphene (PANI/GP) composite nanofibers prepared by self-assembly process using oxidative polymerization of aniline monomer and graphene in the presence of a solution containing poly(methyl vinyl ether-alt-maleic acid) (PMVEA). Characterization of the composite nanofibers was carried out by Fourier transform infrared (FTIR) and Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). SEM images revealed the size of the PANI nanofibers ranged from 90 to 360 nm in diameter and was greatly influenced by the proportion of PMVEA and graphene. The composite nanofibers with an immobilized DNA probe were used for the detection of Mycobacterium tuberculosis by using an electrochemical technique. A photochemical indicator, methylene blue (MB) was used to monitor the hybridization of target DNA by using differential pulse voltammetry (DPV) method. The detection range of DNA biosensor was obtained from of 10−6–10−9 M with the detection limit of 7.853 × 10−7 M under optimum conditions. The results show that the composite nanofibers have a great potential in a range of applications for DNA sensors.

Abstract.The nanostructured hydrophobic rutile phase titanium dioxide and its properties for self-cleaning application were directly synthesized from titanium butoxide (TBOT) precursor deposited on the fluorine doped tin oxide (FTO) substrate through the hydrothermal treatment with different volume of TBOT and adding of Cetyl Trimethylammonium Bromide (CTAB). The samples were characterized respectively by way of field-emission scanning electron microscopy (FE-SEM), water contact angle measurement and Raman spectroscopy for surface analysis system. The FE-SEM results revealed a layer of nanoparticles were growth on the FTO substrate. The surface properties of the samples were studied with a water contact angle measurement. The water contact angle measurement results revealed the hydrophobic of samples as the angle of water droplet on the sample increased. The rutile phase and surface of were confirmed using a Raman spectroscopy.

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In this paper, a side polished multimode plastic optical fiber gas sensor coated with graphene/polyaniline nanocomposite is developed for ammonia gas sensing application. Graphene/polyaniline nanocomposite is deposited onto side polished plastic optical fiber by drop-casting method. The proposed sensor is exposed to different concentration of ammonia varies from 1% to 0.25 % at room temperature. Absorbance response of the gas sensor is monitored and recorded using spectrophotometer system. The absorbance increase linearly with the increase in the ammonia concentrations. The response and recovery time are 24 s and 71.8 s, respectively.