Faculty Publications

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Author: search.filters.author.Anandhan, S.Subject: search.filters.subject.Gas detectors

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    Structure-property relationship of sol-gel electrospun ZnO nanofibers developed for ammonia gas sensing
    (Academic Press Inc. apjcs@harcourt.com, 2014) Senthil, T.; Anandhan, S.
    Zinc oxide (ZnO) based nanomaterials have been used in various gas sensors due to the wide band gap (3.37. eV), large exciton binding energy and high mobility of charge carriers of ZnO. In this work, nanocrystalline ZnO nanofiber mats were synthesized through combined sol-gel electrospinning techniques followed by calcination, in which poly(styrene- co-acrylonitrile) and zinc acetate were used as the binder and precursor, respectively. Average diameter of the ZnO nanofibers decreased from 400 to 60. nm, while their grain size and crystallinity were enhanced by increasing the calcination temperature. Morphology and structure of the ZnO nanofiber mats were characterized by high resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. ZnO nanofiber mats were found to be superhydrophilic (contact angle was close to 0°) by contact angle measurements. The sensitivity of these ZnO nanofibers in detecting gaseous ammonia was tested using an indigenous set up. Due to their high surface area and superhydrophility, these ZnO nanofiber mats were highly sensitive in sensing gaseous ammonia and the sensitivity of these mats increased as a function of their calcination temperatures. © 2014 Elsevier Inc.
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    Highly sensitive and wearable NO2gas sensor based on PVDF nanofabric containing embedded polyaniline/g-C3N4nanosheet composites
    (IOP Publishing Ltd, 2021) Khalifa, M.; Anandhan, S.
    In this study, a highly flexible and wearable nitrogen dioxide (NO2) gas sensor was fabricated based on electrospun poly(vinylidene fluoride) (PVDF)/polyaniline (PANi)/graphitic-carbon nitride (g-C3N4) blend nanocomposite (EBNC). g-C3N4/PANi nanocomposite (GPC) was synthesized by in situ polymerization technique prior to its incorporation into PVDF nanofibers, which ensured uniformity of dispersion. For the comparison study, PVDF/GPC nanocomposite film was fabricated using doctor blade technique. EBNC sensor exhibited high sensitivity, selectivity, reproducibility along with quick response and complete recovery. Electrospinning and GPC synergistically improved the performance of the EBNC based gas sensor. The superior gas sensing ability along with its low cost and the use of scalable electrospinning technique could make this system a promising one for the detection of gaseous NO2. © 2021 IOP Publishing Ltd.
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    Understanding the interplay of solution and process parameters on the physico-chemical properties of ZnO nanofibers synthesized by sol-gel electrospinning
    (Institute of Physics, 2023) Prabhu, N.N.; Rajendra, B.V.; Anandhan, S.; Murthy, K.; Jagadeesh Chandra, R.B.; George, G.; Kumar, B.; Shivamurty, B.
    Aging populations and the increase in chronic diseases worldwide demand efficient healthcare tools for simple, rapid, and accurate diagnosis and monitoring the human health. In this context, gas sensors are used to analyze the type of gas in the breath to diagnose chronic diseases. Metal oxide and ceramic nanofibers (NFs) produced by the electrospinning (ES) method have been investigated for potential use as gas sensors in the engineering and medical sectors. The material and process parameters are the main influencing factors on the functional performance of electrospun metal oxide NFs. Zinc oxide (ZnO) based NFs are used in various gas sensors due to the wide band gap (3.37eV), large exciton binding energy, and high mobility of charge carriers of ZnO. In this research, we made an attempt to study the effect of poly(vinyl alcohol) (PVA) and zinc acetate dihydrate (ZnAc2) concentrations and feed rate, voltage, spinneret tip-to-collector distance (TCD), and pyrolysis temperature on the physical properties of ZnO NFs. An average fiber diameter of 119 nm was obtained after pyrolysis at 600 °C of electrospun fiber produced from an aqueous PVA solution of concentration 15 w% with 7.5 w% ZnAc2 based on the weight of PVA. The grain size, transmittance, structural defects, and band gap energy of NFs were found to increase as a function of the pyrolysis temperature, which could be beneficial for the functional applications of these NFs. © 2023 The Author(s). Published by IOP Publishing Ltd