Graphene oxide-based nanocomposites for outstanding eco-friendly antifungal potential against tomato phytopathogens.

To obtain the collaborative antifungal potential of nanocomposites conjugated with graphene oxide (GO), a combination of GO with chitosan (CS/GO) and GO with chitosan (CS) and polyaniline (PANI/CS/GO) was carried out. The synthesized GO-nanocomposites were recognized by several techniques. Vanillin (Van.) and cinnamaldehyde (Cinn.) were loaded on the prepared nanocomposites as antioxidants through a batch adsorption process. In vitro release study of Van. and Cinn. from the nanocomposites was accomplished at pH 7 and 25°C. The antimicrobial activity of GO, CS/GO, and PANI/CS/GO was studied against tomato Fusarium oxysporum (FOL) and Pythium debaryanum (PYD) pathogens. The loaded ternary composite PANI/CS/GO exhibited the best percent of reduction against the two pathogens in vitro studies. The Greenhouse experiment revealed that seedlings' treatment by CS/GO/Van. and PANI/CS/GO/Van significantly lowered both disease index and disease incidence. The loaded CS/GO and PANI/CS/GO nanocomposites had a positive effect on lengthening shoots. Additionally, when CS/GO/Cinn., CS/GO/Van. and PANI/CS/GO/Van. were used, tomato seedlings' photosynthetic pigments dramatically increased as compared to infected control. The results show that these bio-nanocomposites can be an efficient, sustainable, nontoxic, eco-friendly, and residue-free approach for fighting fungal pathogens and improving plant growth.

Investigating the Adsorption Behavior of Polyaniline and Its Clay Nanocomposite towards Ammonia Gas.

Air pollution and control of gaseous air pollutants are global concerns. Exposure to these gaseous contaminants causes several health risks, especially exposure to irritant gases such as ammonia (NH3). Furthermore, the application of smart polymeric nanocomposites in environmental applications has gained significant interest in recent years. In this study, aniline was polymerized without and with clay using a carbon dioxide (CO2)-assisted polymerization technique, yielding PANI and PANC samples, respectively. The samples were characterized using different methods, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and Brunner Emmett Teller (BET). The synthesized nanomaterials were utilized as gas adsorbents using a fixed bed reactor to investigate their adsorption behavior towards NH3. Three inlet NH3 concentrations were tested (35-150 ppm). The results revealed that the adsorption capacities of PANC nanocomposites were higher than nanostructured PANI for the studied concentrations. The adsorption capacities were 61.34 mgNH3/gm for PANC and 73.63 mgNH3/gm for PANI at the same inlet concentration (35 ppm). The highest NH3 adsorption capacity recorded was 582.4 mg NH3/gm, for PANC. This study showed the impressive adsorption behavior of the prepared PANI and PANC nanomaterials towards NH3 gas. Consequently, nanostructured PANI and PANC can be promising adsorbents that can be utilized to control different gaseous air pollutants.

Improvement of the Uniformity and Electrical Properties of Polyaniline Nanocomposite Film by Addition of Auxiliary Gases during Atmospheric Pressure Plasma Polymerization.

The morphological and chemical properties of polyaniline (PANI) nanocomposite films after adding small amounts of auxiliary gases such as argon, nitrogen, and oxygen during atmospheric pressure (AP) plasma polymerization are investigated in detail. A separate gas-supply line for applying an auxiliary gas is added to the AP plasma polymerization system to avoid plasma instability due to the addition of auxiliary gas during polymerization. A small amount of neutral gas species in the plasma medium can reduce the reactivity of monomers hyperactivated by high plasma energy and prevent excessive crosslinking, thereby obtaining a uniform and regular PANI nanocomposite film. The addition of small amounts of argon or nitrogen during polymerization significantly improves the uniformity and regularity of PANI nanocomposite films, whereas the addition of oxygen weakens them. In particular, the PANI film synthesized by adding a small amount of nitrogen has the best initial electrical resistance and resistance changing behavior with time after the ex situ iodine (I2)-doping process compared with other auxiliary gases. In addition, it is experimentally demonstrated that the electrical conductivity of the ex situ I2-doped PANI film can be preserved for a long time by isolating it from the atmosphere.

3D hierarchical graphene/CNT with interfacial polymerized polyaniline nano-fibers.

In this work Polyaniline (PANI) fiber has been synthetized by the interfacial polymerization method. The thermal behavior of graphene - multiwall carbon nanotubes (MWCNs) composite material (C-Mix) blended with PANI fiber was investigated. Graphene was prepared by thermal reduction of the fabricated graphene oxide (GO) using modified Hummers' method. SEM measurement reveals that MWCNTs were well organized within 2D large surface area graphene nano-sheets to form 3D carbon-base hierarchical structure, and PANI was mixed as a binder polymer matrix. Structural measurements confirm the formation of wide area graphene sheets with crumples, wrinkles, and folds around the edges. Transmission electron microscopy (TEM) images agreed with the well distribution of CNTs within graphene nano-sheets. Also, the surface morphology of the synthesized composites has a spherical regular agglomeration of PANI granular structure on wide area graphene nano sheets with CNT embedded. The change in the existed phonon modes of the fabricated nano-composite was analyzed using Raman spectroscopy. Moreover, Seebeck coefficient changes from +132.4 µV/K to -10.3 µV/K after adding carbon-based materials which reflects the reverse of predominate carriers by doping PANI with carbon-based material. It has been noticed that there is an enhancement of thermal conductivity of the fabricated composite with respect to neat polymer. Hence, we propose that 3D carbon structure with PANI construct a stable N-Type thermoelectric material.