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    Sustainability in magnetic metal-carbon nanocomposites: a comprehensive review of manufacturing, characterization, and applications
    (EDP Sciences, 2024-07) Belgamwar, Sachin U.
    Magnetic metal-carbon nanocomposites (MMCN) are emerging as sustainable materials, consisting of magnetic metals or alloys and carbon-based materials like CNT, graphene (Gr), carbon fiber (CF), and activated carbon. These materials possess unique magnetic properties that depend on various factors, such as preparation conditions, metal content, and phase composition. Incorporating carbon-based materials into magnetic metals has been observed to enhance their magnetic properties, including magnetic strength and moment. Researchers employ a range of tests to characterize these materials, such as FTIR, XRD, FESEM, TEM, BET, and VSM. Carbon-based materials such as CNT, graphene, etc., have been used as filler materials to reinforce the metal matrix because of their sustainability, tendency to integrate, and low cost. Further, they enhance the tribological performance and mechanical strength, provide corrosion resistance and improve electrical and thermal properties. Additionally, the addition of filler magnetic material in single or hybrid form into the carbon matrix increases the scope of application of MMCN. These composites are widely used in the application of biomedical, semiconductors, tribology, fuel cells, etc. In the present study, a comprehensive review has been carried out to provide a view of the fabrication aspect of the MMNC and to understand the role of the reinforcement method used to fabricate the composites. Finally, it covers different uses of the MMCN, which can lead to an eco-friendly environment.
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    Carbon-metal oxide nanocomposites for selective detection of toxic and hazardous volatile organic compounds (VOC) – A review
    (Elsevier, 2022-04) Hazra, Arnab
    Recently carbon nanostructures i.e. graphene and its derivatives, carbon nanotubes (CNT) and fullerene combined with different metal oxides have provided researchers a lot of opportunities for the sensing of volatile organic compounds (VOCs). The synergistic effect of both nanocarbon and metal oxide assuredly makes the nanocomposite suitable for reliable and stable sensors. Studies on hybrid structures by many researchers had shown improved sensing parameters in terms of high sensitivity, selectivity, fast response and recovery time at room temperature. In the present review we have reported the nanocomposites of carbon nanostructures and metal oxides for efficient and selective detection of toxic and hazardous VOCs.
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    Fullerene- MoSe2 nanocomposite-based sensor for selective detection of formaldehyde
    (IEEE, 2023) Hazra, Arnab
    Selective detection of volatile organic compound is crucial for medical applications. Here, we have synthesized fullerene (C 60 )-MoSe2(F-MoSe2) composite for selective detection of formaldehyde at room temperature. MoSe2 nanoflowers were synthesized by hydrothermal method and further functionalized with 0.05 wt% of fullerene solution. The nanocomposite was characterized with different characterization tools. The VOC sensing measurements revealed the natural selectivity of the F-MoSe2 sensor towards formaldehyde compared to other different VOCs with a significant response of 35% for 50 ppm at room temperature. Moreover, formaldehyde selective behavior was possible due to improved surface area and highly oxygen-functionalized surface after fullerene modification.
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    Prediction of drilling induced delamination and circularity deviation in GFRP nanocomposites using deep neural network
    (Elsevier, 2022) Sharma, Panchagnula Jayaprakash; Jasti, Naga Vamsi Krishna
    Drilling of Glass Fiber Reinforced Polymer (GFRP) nanocomposites is most prevailing topic to understand the composite behaviour under different cutting conditions. The present study is mainly focused on prediction of drilling output responses such as delamination factor and circularity error randomly with the help of deep neural network (DNN) model. L9 orthogonal array is used for experimentation. Drilling operation is performed on 0.3 wt% multi-walled carbon nano tubes reinforced GFRPs with solid carbide, TiCN and TiAlN coated (6 mm- diameter) twist drills. Based on experimental results, two different deep neural network models are prepared with single and double hidden layers by varying node numbers such as 8, 16, 32, 64, and 128. Thrust force, Acoustic Emission RMS voltage, and drill type (coating) are considered as input to the neural network and delamination factor at exit, circularity error are treated as predicted output responses for the given network model. The revealed predicted results recommended that two hidden layers with 32 nodes network model give the lowest absolute error of 0.08% and 3.13% in delamination factor and circularity errors respectively. Similarly, the highest absolute error is identified as 4.19% in delamination factor and 13.14% in circularity error by single hidden layer with 128 nodes. Therefore, it is urged that DNN is the most suitable modelling technique for prediction of drilling responses on GFRP nano composites.
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    The influence of Fe3O4@GNP hybrids on enhancing the EMI shielding effectiveness of epoxy composites in the X-band
    (Elsevier, 2020-07) Etika, Krishna Chitanya
    In this work, the electromagnetic interference (EMI) shielding effectiveness in the X band frequency range of 8–12.4 GHz of epoxy nanocomposites containing Fe3O4 nanoparticles decorated graphene nanoplatelets (i.e., Fe3O4@GNP hybrids) is investigated. The hybrid nanostructures were synthesized in situ by a simple co-precipitation technique and were incorporated into the epoxy matrix by melt blending following a solvent-less approach. Scanning electron microscopy performed on the hybrid nanostructures revealed a good distribution of Fe3O4 nanoparticles on the GNP sheets in the hybrid. A series of epoxy nanocomposites containing varying content of Fe3O4@GNP, GNP and/or Fe3O4 nanoparticles were synthesized and compared for their EMI shielding effectiveness. The SEM of the composite cross-section reveals good filler dispersion in the composites. Overall the nanocomposites containing Fe3O4@GNP hybrids exhibited enhanced EMI shielding performance when compared to samples containing equivalent loading of only GNP and/or Fe3O4. The 1 mm thick composite sample containing 1:3 (wt/wt) Fe3O4: GNP hybrid attenuated 89 % of incident wave power and exhibited an EMI shielding effectiveness value of 9.6 dB in the X-band.
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    Environmentally friendly low-cost graphene oxide-cellulose nanocomposite
    (Elsevier, 2022-07) Etika, Krishna Chitanya
    This study primarily aims to develop a simple, cost-effective, eco-friendly nanocomposite filter for dye removal by adsorption. In this work, graphite oxide and graphene oxide were synthesized using a modified Hummers’ process and used to fabricate nanocomposite filters by co-precipitation reactions. Scanning electron microscopy and X-ray diffraction were performed on nanofillers revealing crystallographic and morphological properties of the nanofillers.
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    Fabrication of novel thin film capacitor based on PVA/ZnO nanocomposites as dielectric material
    (Springer, 2020-11) Nair, Sindhu S.
    A three-layer thin film capacitor was designed and fabricated with PVA/ZnO nanocomposite as dielectric material. Addition of ZnO nanoparticles showed change in dielectric constant, which varied with frequency and weight percentage. ZnO nanoparticles of weight percentage of 0.5% is chosen for the synthesis of nanoparticles with a grain size of 54 nm, using cost-effective and simple co-precipitation method. It is a low-cost method for large-scale production without impurities. The agglomeration was reduced by adding the starch molecules so that the O–H functional groups could hold together to the nanoparticles at the earlier nucleation stage and can be removed when purification by centrifugation is done. Fourier-transform infrared spectroscopy analysis showed peaks due to the O–H groups in the polymer backbone, CH2 asymmetric and symmetric stretching, C–C stretching and Zn–O stretching, respectively, indicating formation of the proper film. From the profilometer, the thickness was calculated as 195.73 nm for the dielectric film. The fabricated device showed capacitance of 210 nF m−2 in par with the theoretical value (254.451 nF m−2) at 298 K.
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    Impact on bulk and interfacial dielectric properties of nematic liquid crystals due to silver nanoparticles
    (AIP, 2021-09) Manjuladevi, V.; Gupta, Raj Kumar
    Doping of nanomaterials into the liquid crystals (LC) can greatly enhance the physical properties of host LC. Since, it is not possible to obtain all the desired parameters of a display device in a single LC, several researchers are trying to optimize the display parameters by using different nanomaterials of different functionalization. In this work, we report the effect of hexane thiol functionalised silver nanoparticles (f-AgNPs) on the dielectric relaxation and electrical properties of nematic liquid crystal 4-trans-pentyal-cyclohexyl cyanobenzene (5PCH) in the homeotropic alignment. The impedance spectroscopy response of pure and f-AgNPs doped nanocomposites of 5PCH are studied in the frequency range of 20Hz - 12MHz. The electrical properties such as bulk capacitance, electrode resistance, double layer capacitance, bulk resistance and Warburg diffusion coefficients were determined by fitting a suitable equivalent electrical circuit model to the experimental data. Temperature dependence of the dielectric relaxation frequency for pure and f-AgNPs doped nanocomposites of 5PCH were also investigated.
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    Studies on Thin Films of Hexa-Alkoxy Triphenylene(HAT5) and Composite of HAT5-TiO2 Nanoparticles
    (American Scientific Publishers, 2014-05) Manjuladevi, V.; Gupta, Raj Kumar
    The studies on discotic liquid crystals are important not only for basic scientific research but also for industrial applications. It can be potentially employed for the fabrication of devices in photovoltaics, organic solar cells and organic LEDs. Hexa-alkoxy triphenylene (HAT5) is one of the commonly studied discotic liquid crystals. We formed Langmuir monolayer of pure HAT5 on ultrapure water subphase. We have studied the effect of doping the monolayer of HAT5 with different concentration of TiO2 nanoparticles on the surface pressure-area isotherms of the Langmuir monolayer. We observed considerable shift in the isotherms towards lower area per molecule on increasing the concentration of TiO2. We deposited the Langmuir-Blodgett (LB) films of pure HAT5 and HAT5+TiO2 (5 and 20% by weight) nanocomposites on the glass substrates. We characterized the films using UV-Vis spectrophotometer and atomic force microscope (AFM). The energy gap is found to decrease with increasing concentration of TiO2 nanoparticles in the HAT5 matrix. It decreases rapidly with increasing the target surface pressure of LB deposition. The AFM images reveal higher density of clusters of TiO2 nanoparticles with the increase in concentration of the nanoparticles in HAT5 monolayer. Such increase in the density may results in reduction in energy gap of the LB films of the nanocomposites.
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    Detection of cadmium ion in water using films of nanocomposite of functionalized carbon nanotubes and anionic polymer
    (AIP, 2018-05) Manjuladevi, V.; Gupta, Raj Kumar
    Presence of cadmium in drinking water is one of the major threats to human health. According to international standards, the maximum permission concentration of cadmium ion in drinking water should be less than 0.002 to 0.010mg/l (2-10 ppb). It is one of the major contaminants in potable water in western part of Indian subcontinent. It is found up to 2.3 to 8.6 mg/l in Rajasthan water. In this article, we report our study on detection of cadmium ion in water employing a sensing layer of nanocomposites of functionalized single walled carbon nanotubes (SWCNTs) and polyacrylic acid (PAA). The film was deposited onto 5 MHz AT-cut quartz crystal of a quartz crystal microbalance (QCM). The response was collected in both static and dynamic mode. We obtained a linear response curve in a given concentration range of cadmium ion indicating the suitability of the functional layer for cadmium ion detection in water. The surface morphology of the functional layer was studied using atomic force microscope before and after sensing.