Publications

In the present work, sulfonated graphene oxide and sulfonated poly(1,4-phenylene ether-ether-sulfone) were blended with polyvinylidene fluoride to create a novel ionic polymer-metal composite actuator with enhanced performance. An ionic polymer-metal composite membrane in the protonated form was prepared by casting a composite blend of sulfonated poly(1,4-phenylene ether-ether-sulfone), polyvinylidene fluoride and sulfonated graphene oxide onto a plating of platinum metal as the electrode. The degree of sulfonation of poly(1,4-phenylene ether-ether-sulfone) was characterized using ion-exchange capacity measurements. Energy dispersive X-ray and transmittance electron microscopy analyses were carried out to analyze the chemical composition and detailed structure. Deposition of the platinum electrode and the surface morphology of the proposed ionic polymer-metal composite actuator were assessed using scanning electron microscopy analysis. The electrical properties were measured using cyclic voltammetry, linear sweep voltammetry and proton conductivity. These measurements confirmed the better actuation performance of the fabricated ionic polymer-metal composite actuator compared to other expensive ionic polymer-based actuators, in terms of its high ion-exchange capacity, good proton conductivity, high current density and large bending deflection. The robust, flexible and mechanically strong membrane actuator, fabricated <i>via</i> the synergistic combination of sulfonated poly(1,4-phenylene ether-ether-sulfone), polyvinylidene fluoride and sulfonated graphene oxide, has considerable potential as an actuator material for robotic, bio-mimetic and other applications.

Saturated heterocyclic acetals are useful fragments in organic synthesis and other fields. Herein, C(sp³)-H dehydrogenative cross-couplings of ethers, tetrahydrothiophenes, and pyrrolidines were achieved under visible light irradiation by using iodobenzene and an in situ-formed gold complex. The broad functional group compatibility and substrate scope indicate that our strategy is a promising way to synthesize acetal analogues. The method was successfully applied in late-stage modifications of bioactive molecules. Gram scale syntheses and mechanistic studies are also presented.

Nanocomposites of Ag/TiO(2) nanowires with enhanced photoelectrochemical performance have been prepared by a facile solvothermal synthesis of TiO(2) nanowires and subsequent photoreduction of Ag(+) ions to Ag nanoparticles (AgNPs) on the TiO(2) nanowires. The as-prepared nanocomposites exhibited significantly improved cathodic photocurrent responses under visible-light illumination, which is attributed to the local electric field enhancement of plasmon resonance effect near the TiO(2) surface rather than by the direct transfer of charge between the two materials. The visible-light-driven photocatalytic performance of these nanocomposites in the degradation of methylene blue dye was also studied, and the observed improvement in photocatalytic activity is associated with the extended light absorption range and efficient charge separation due to surface plasmon resonance effect of AgNPs.

The 4-NPHyd (4-nitrophenylhydrazine) electrochemical sensor assembled using wet-chemically prepared ZnO/SnO2 nanoparticle (NPs) decorated a glassy carbon electrode (GCE) with conductive Nafion binder. The synthesized NPs characterized by XPS, ESEM, EDS, and XRD analysis. The calibration of the proposed sensor obtained from current versus concentration of 4-NPHyd found linear over a concentration (0.1 nM ~ 0.01 mM) of 4-NPHyd, which denoted as the dynamic range (LDR) for detection of 4-NPHyd. The 4-NPHyd sensor sensitivity calculated using the LDR slope considering the active surface of GCE (0.0316 cm2), which is equal to be 7.6930 µAµM/cm2, an appreciable value. The detection limit (LOD) at signal/noise (S/N = 3) estimated, and outstanding lower value at 94.63±4.73 pM perceived. The analytical parameters such as reproducibility, long-term performing ability and response time are found as appreciable. Finally, the projected sensor shows exceptional performances in the detection of 4-NPHyd in environmental samples.

A new water-insoluble organic dye, namely, 2-((10-decyl-10H-phenothiazin-3-yl)methylene)malononitrile, was synthesized and fully characterized. It was envisioned that photocatalytic decolourization of a dye-containing long chain would pave the way for the photocatalytic remediation of wastewater containing toxic hydrophobic organic pollutants. Two commercially available nanoparticles, ZnO and TiO2, were selected, and their photocatalytic decolourization of the dye from aqueous medium were compared. The black UV light irradiation of the colored samples in the presence of TiO2 (P25) or ZnO resulted in their decolourization and the photocatalytic activity observed for TiO2 (P25) was better than that of ZnO. The kinetic of decolourization indicated that the process was first-order from which the rate constant was calculated. Also, the effect of pHs on the kinetic of decolourization revealed a negligible effect, indicating that the pH, although it affects the catalysts but has no effect on the organic-based hydrophobic dye and thus no effect on the photocatalytic process.