Polyaniline (PA)-MOF nanocomposites have been successfully synthesized through an in-situ chemical oxidative polymerization of aniline in the presence of nano-sized iron trimestate (named as MIL-100(Fe)) particles, which was prepared by a microwave-irradiation method. Water sorption and humidity sensing results clearly showed that water sorption rate and humidity sensitivity are dramatically enhanced by the composites using nano-sized MIL-100(Fe) as compared with that using micrometer-sized MIL-100(Fe) particles.

Poly(o-toluidine) (POT) coatings were electrodeposited as corrosion protective coatings on low carbon steel (LCS), 304 stainless steel (SS) and copper (Cu) substrates. POT coatings on metal substrates have been carried out under cyclic voltammetric conditions in an aqueous sodium salicylate solution. The role of substrates during electrochemical polymerization also studied. Then, POT coatings were characterized by UV-visible (UV) and Fourier transforms infrared (FTIR) spectroscopic techniques. Corrosion resistance performances of these coatings were studied in NaCl solution by potentiodynamic polarization measurement and electrochemical impedance spectroscopy (EIS). The results reveal that POT coating on metals prevents corrosion, reduces the corrosion rate.

ZnO nanorods (diameters∼25 nmand lengths∼145-150 nm) were synthesized by using a simple solochemical method and their LPG sensing properties were investigated.The ZnO nanorods exhibited outstanding gas sensingcharacteristics such as, higher gas response (∼502 to 50ppm LPG at 300 •C), extremely rapid response(∼6-7 s), fast recovery (∼6-7 s), excellent reproducibility, good sensing selectivity and relatively lower operating temperature(∼300•C). The experimental results clearly demonstrate the potentialof using the ZnO nanorods as sensing material in the fabrication of LPG sensors.

We report a fast-responding and selective room temperature liquefied petroleum gas (LPG) sensor based on poly(o-anisidine)–cerium oxide (POA–CeO2) nanocomposites.

The In 2 O 3 nanocubeswere successfully synthesized without any templates by calcining the In(OH) 3 precursor in air at 300 o C for 2 h and their H 2 sensing characteristics were investigated.The In(OH) 3 precursor was prepared through a wet chemical route at room temperature (27 o C)using InCl 3 ,4H 2 O and NH 4 OHas starting materials.The formation ofIn 2 O 3 nanocubes was confirmed by X-ray diffraction measurement (XRD), X-ray photoelectron spectroscopy (XPS)and transmission electron microscopy (TEM)analysis.The In 2 O 3 nanocubes exhibit excellentH 2 sensing properties such as, high gas response (~130 to 50 ppm H 2 at 325 o C), extremely rapid response (1s), fast recovery (4-5 s), excellent repeatability and good selectivity.Furthermore, the lower detection limit is ~3.87 ppm, which is lower than the permissible explosive limit for H 2 .The experimental results demonstrate the potential of theIn 2 O 3 nanocubes as sensing material in the fabrication of hydrogen sensors.

We report the fabrication of a highly sensitive and fast humidity sensor based on cerium oxide (CeO2) nanoparticles, which were prepared at low cost via a simple non-isothermal precipitation method. The asprepared CeO2 nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy( TEM) and the results indicated the formation of face centered cubic phase of CeO2 with average crystallite size of approximately 10-12 nm. Humidity sensors based on CeO2 nanoparticles exhibit high and linear response within the whole relative humidity (RH) range of 11-97% at an operating frequency of 60 Hz. The corresponding impedance changes by approximately three orders of magnitude within the entire humidity range from 11% to 97% RH. The response and recovery times are about 2-3 and 9-10 s, respectively, when RH was switched between 11% and 97%. Furthermore, the sensors also show relatively small hysteresis, excellent reproducibility, long term stability and broad range of operation (11-97% RH). The complex impedance spectra of the sensor at different RHs and the equivalent circuit were analyzed to explore the humidity-sensing mechanism. This study demonstrates that the CeO2 nanoparticles prepared by non-precipitation method can be used as the humidity-sensing material for the fabrication of humidity sensors. (C) 2014 Elsevier B. V. All rights reserved.

The low carbon steel (LCS) electrodes were polarized under cyclic voltammetric conditions in sodium oxalate solution at room temperature in order to understand the different processes that occur at the electrode surface. This study suggests that, a continuous dissolution of the LCS electrode occurs in oxalate solution. In order to understand the observed Cyclic voltammetry (CV) results, taken the X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM) of the LCS electrode polarized in 0.1 M sodium oxalate solution . The polypyrrole (PPY) coatings were electrochemically synthesized on LCS substrates by cyclic voltammetric method from an aqueous solution of sodium oxalate. The resulting coatings were characterized by CV, Fourier transform infrared (FTIR) spectroscopy, UV-visible absorption spectroscopy, XRD measurements and SEM. These characterizations, clearly reveals that the PPY coating is uniform and compact. The surface of the coating is characterized by a globular texture. The coatings are strongly adherent to the LCS surface.

This paper reports a simple and rapid microwave-assisted method for synthesizing cerium oxide (CeO2) nanoparticles for the fabrication of high-performance humidity sensors. The humidity-sensing investigation reveals that the sensor based on CeO2 nanoparticles exhibits a high and linear response within the entire relative humidity (RH) range of 11–97% at an operating frequency of 60Hz. The corresponding impedance changes by approximately three orders of magnitude within the entire humidity range from 11% to 97%. The response and recovery times are approximately 3 and 16s, respectively. Additionally, the sensor exhibits a rapid and reversible response characterized by a very small hysteresis (∼1%RH), excellent repeatability, long term stability and a broad range of operation (11–97%RH). The Nyquist impedance plots of the sensor at different RHs were used to elucidate the sensor's humidity-sensing mechanism via an electrical equivalent circuit. The experimental results provide a possible method for the rapid synthesis and fabrication of high-performance humidity sensors based on CeO2 nanoparticles.

The polypyrrole (PPY) coatings were electrochemically synthesized on low carbon steel (LCS) substrates by cyclic voltammetric method from an aqueous solution of sodium oxalate. The corrosion protection performance of PPY coatings on LCS were studied in different corrosive environments such as, aqueous 3% NaCl, 0.01 M Na2SO4 and tap water. This corrosion protection performance was evaluated by potentiodynamic polarization measurement. The result of the potentiodynamic polarization demonstrates that the PPY coating has ability to protect the LCS against corrosion. The corrosion potential (Ecorr) was about 256 mV more positive in aqueous 3% NaCl for the PPY coated LCS than that of bare LCS and significantly reduces the corrosion rate of LCS. It was also observed that the PPY coating has ability to protect LCS against corrosion in aqueous Na2SO4 and tap water. Keywords— Conducting polymer coatings, Polypyrrole coatings, Corrosion, Corrosive media ..

Zinc stannate (ZnSnO3) cubic crystallites have been successfully synthesized by hydrothermal reaction at 140°C. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) have been employed to characterize the crystal structure and morphology of the as-synthesized ZnSnO3. The ZnSnO3 cubic crystallites exhibited selective sensing performance towards H2 in terms of higher gas response, rapid response-recovery, repeatability and relatively lower operating temperature. This experimental result demonstrates that the synthesized ZnSnO3 cubic crystallites have noteworthy H2 sensing characteristics which make them a promising material for the fabrication of high performance H2 sensor.

Electrochemical polymerization of the aniline, o-anisidine and o-toluidine coatings on low carbon steel has been carried out under galvanostatic conditions in an aqueous oxalic acid solution. The E–t curves show three distinct stages – dissolution of the low carbon steel surface and formation of polycrystalline iron oxalate interphase, complete passivation of low carbon steel surface and the electrochemical polymerization of respective monomer(s). To understand the role of monomer(s) during the electrochemical polymerization process, the passive interphase samples were characterized by X-ray photoelectron spectroscopy. The results of this study show that monomer(s) are taking a part in first stage of electrochemical polymerization and passivation time depends on the type of monomer(s) present in electrolyte.

Poly(o-anisidine)-tin oxide (POA-SnO2) nanocomposites has been investigated for the fabrication of low temperature operative (100 °C) liquefied petroleum gas (LPG) sensor. The POA-SnO2 nanocomposites have been synthesized through an in situ chemical polymerization of o-anisidine in presence of SnO2 nanoparticles. The POA-SnO2 nanocomposite shows better LPG sensing properties than that of pure POA. The nanocomposite with 50 wt. % SnO2 exhibits an excellent LPG sensing characteristics at the operating temperature of 100 °C such as higher relative gas response (∼23.47% to 3.4% of LPG), extremely rapid response (∼6 s), fast recovery (∼33 s), good reproducibility, and remarkable selectivity. The application of POA-SnO2 nanocomposites for fabrication of the LPG sensor was demonstrated.

Poly(2,5-dimethoxyaniline)-tin oxide (PDMA-SnO2) nanocomposites were synthesized successfully for the first time through an in situ chemical polymerization of 2,5-dimethoxyaniline in the presence of SnO2 nanoparticles of 25-40 nm in diameters. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were used to characterize the PDMA-SnO2 nanocomposites. The characterization results confirmed the polymerization of 2,5-dimethoxyaniline and the strong interaction between PDMA and SnO2 nanoparticles. Humidity sensing characteristics such as humidity response-relative humidity (RH) property, humidity hysteresis, response and recovery times, reproducibility and stability of PDMA-SnO2 have been investigated. The nanocomposite with 50 wt% of SnO2 exhibited better humidity sensing properties than pure PDMA, such as rapid response (similar to 3 s), fast recovery (similar to 43 s), hysteresis within 5% and excellent reproducibility. Plausible humidity sensing mechanism of PDMA-SnO2 nanocomposite is also discussed.

This work reports humidity sensing properties of ZnSnO3 cubic crystallites synthesized by a hydrothermal method. ZnSnO3 cubic crystallite film exhibits excellent humidity sensing characteristics such as fast response time (∼7s), rapid recovery (∼16s), linearity, hysteresis within 3.5%, excellent repeatability, good stability and broad range of operation (11–97% RH). The application of ZnSnO3 cubic crystallites for construction of humidity sensors is demonstrated.

This paper demonstrates that metastable compounds can be synthesized on solid surface via pulsed laser induced processes at the liquid solid interface. Specifically, it is shown that the metastable oxides of iron can be obtained when an iron foil immersed in water is treated with Ruby Laser pulses [ λ =693.4 nm, pulse width 30 ns, energy density 10 J/cm2].The oxide has been characterized by using the techniques of conversion electron Mössbauer spectroscopy, X-ray diffraction and Rutherford Backscattering Spectrometry. The oxygen concentration near the surface as well as the depth scale over which it falls to zero can be varied by changing the laser treatment parameters such as pulse to pulse overlap, energy per pulse etc. A near-surface composition of ∼50 at.% and a depth scale of oxygen incorporation of a few thousand A° can be easily achieved. The phase transformation of a metastable oxide under thermal treatment is also explored. The mechanisms which could be responsible for the observed effects are commented upon. Some iron foils have been treated in air using comparable laser pulse parameters to obtain a comparision between treatment in air and liquid. Interestingly these foils show presence of √-Fe, which is a high temperature phase of iron known to be unstable at room temperature when pure. Other possible applications of laser processing of solids in liquid media are also discussed.

Polyaniline (PANI) coatings were electrochemically synthesized on nickel (Ni) coated mild steel (MS) and their corrosion protection properties were investigated. In this work, the Ni layer (∼1μm thick) was electrodeposited on MS under galvanostatic condition. Thereafter, the PANI coating was deposited over the Ni layer from aqueous salicylate medium by using cyclic voltammetry. These bi-layered composite coatings were characterized by cyclic voltammetry, UV–vis absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The corrosion protection properties of Ni coated MS (Ni/MS) and PANI coated Ni/MS (PANI/Ni/MS) were investigated in aqueous 3% NaCl by using open circuit potential (OCP) measurements, potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). It was shown that the top layer of PANI exhibits a lower porosity behavior with respect to Ni coating and reduces the corrosion rate of Ni/MS almost by a factor of 3500 and increases the lifetime of Ni coating.

Nanostrucutred spinel ZnCo2O4 (∼26–30nm) was synthesized by calcining the mixed precursor (consisting of cobalt hydroxyl carbonate and zinc hydroxyl carbonate) in air at 600°C for 5h. The mixed precursor was prepared through a low cost and simple co-precipitation/digestion method. The transformation of the mixed precursor into nanostructured spinel ZnCo2O4 upon calcinations was confirmed by X-ray diffraction (XRD) measurement, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). To demonstrate the potential applicability of ZnCo2O4 spinel in the fabrication of gas sensors, its LPG sensing characteristics were systematically investigated. The ZnCo2O4 spinel exhibited outstanding gas sensing characteristics such as, higher gas response (∼72–50ppm LPG gas at 350°C), response time (∼85–90s), recovery time (∼75–80s), excellent repeatability, good selectivity and relatively lower operating temperature (∼350°C). The experimental results demonstrated that the nanostructured spinel ZnCo2O4 is a very promising material for the fabrication of LPG sensors with good sensing characteristics. Plausible LPG sensing mechanism is also discussed.

The α-Fe2O3 nanorods were successfully synthesized without any templates by calcining the α-FeOOH precursor in air at 300°C for 2h and their LPG sensing characteristics were investigated. The α-FeOOH precursor was prepared through a simple and low cost wet chemical route at low temperature (40°C) using FeSO4·7H2O and CH3COONa as starting materials. The formation of α-FeOOH precursor and its topotactic transformation to α-Fe2O3 upon calcination was confirmed by X-ray diffraction measurement (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. The α-Fe2O3 nanorods exhibited outstanding gas sensing characteristics such as, higher gas response (∼1746–50ppm LPG at 300°C), extremely rapid response (∼3–4s), relatively slow recovery (∼8–9min), excellent repeatability, good selectivity and lower operating temperature (∼300°C). Furthermore, the α-Fe2O3 nanorods are able to detect up to 5ppm for LPG with reasonable response (∼15) at the operating temperature of 300°C and they can be reliably used to monitor the concentration of LPG over the range (5–60ppm). The experimental results clearly demonstrate the potential of using the α-Fe2O3 nanorods as sensing material in the fabrication of LPG sensors. Plausible LP G sensing mechanism of the α-Fe2O3 nanorods is also discussed.

The present investigation deals with the preparation of CO sensor based on SnO2. In this work, SnO2 films were prepared by standard screen-printing method. These films were characterized by x-ray diffraction (XRD) measurements, spectroscopy and scanning electron microscopy (SEM). These films exhibit high sensitivity, excellent selectivity, fast response and recovery to CO gas at 300 degrees C in air atmosphere.

Guizotia abyssinica Cass. (niger, Asteraceae) is an important but neglected edible oil seed crop. It is cultivated in the Indian subcontinent, Ethiopia and East African countries. Meager information is available on its physiology as compared to other crops. The present investigation reports the influence of NaCl stress (0, 20, 40, 60, 80 and 100 mM) on seed germination, growth, chlorophyll content, osmolyte accumulation and antioxidant enzyme activity in four cultivars (‘IGP-76’, ‘GA-10’, ‘No. 71’ and ‘IGPN-2004’) of niger. The observations were recorded on the 7 day after salt treatment. Increasing salt stress greatly reduced the seed germination percentage in ‘GA-10’ than ‘No. 71’ and ‘IGPN-2004’, whereas ‘IGP-76’ was least affected. A similar pattern was observed for growth (shoot and root length), formation of biomass and total chlorophyll content. Maximum damage to the cellular membrane, as evidenced by a higher accumulation of malondialdehyde, occurred in ‘GA-10’, whereas least damage to cellular membranes was observed in ‘IGP-76’. GB content and catalase activity were higher in ‘IGP-76’ than ‘No.71’, ‘IGPN-2004’ and ‘GA-10’. Therefore, ‘IGP-76’ is a salt-tolerant cultivar and ‘GA10’ is more sensitive to salt stress than ‘No. 71’ and ‘IGPN-2004’. _____________________________________________________________________________________________________________