Faculty Publications
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Item Comparative Studies on Crystalline and Amorphous Vinylidene Fluoride Based Fibrous Polymer Electrolytes for Sodium-Ion Batteries(Springer Singapore, 2020) Janakiraman, S.; Khalifa, M.; Biswal, R.; Ghosh, S.; Anandhan, S.; Adyam, A.In the present work, electrospun poly (vinylidene fluoride) (PVDF) and poly (vinylidene fluoride-co hexafluropropylene) (P(VdF-co-HFP)) fibrous membranes have been compared. Porous homo and copolymer fiber-based membranes with an interconnected structure, high porosity, large electrolyte uptake were prepared by an electrospinning route. The effect of crystallinity in terms of X-ray diffraction (XRD) was investigated for the fibrous polymer membranes (FPMs). The surface morphology of the FPMs is evaluated by field emission scanning electronmicroscopy (FESEM). The FPMswere soaked in 1MNaClO4-ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1, vol%) solution to form fibrous polymer electrolytes (FPEs). The ionic conductivity of copolymer showed 1.126 mS cm−1 under ambient temperature (at 28 °C) higher than the homopolymer (0.79 mS cm−1) because of HFP unit. The electrochemical stability window of the copolymer membrane also enhanced and stable up to 4.9 V versus Na+/Na suitable for high voltage sodium rechargeable batteries. When tested with Na066Fe0.5Mn05O2 as cathode and Na metal as an anode, the cycle performance significantly improved for the copolymer. © Springer Nature Singapore Pte Ltd. 2021.Item Sol-gel electrospinning of diverse ceramic nanofibers and their potential applications(Elsevier, 2020) George, G.; Senthil, T.; Luo, Z.; Anandhan, S.Ceramics are composed of both metallic and nonmetallic elements and commonly exist as compounds of oxides, nitrides, and carbides. Two decades back, the use of ceramics was limited to a handful of applications, as in household utilities and some industrial uses. In the era of nanotechnology, the definition and application of materials are altered, especially in the case of ceramics. By the development of various fabrication techniques of nanostructured ceramics, the scope of ceramic materials is radically transformed, making them the most beneficial among the materials ever designed for several critical applications. The fabrication of ceramic nanostructures is challenging from an industrial point of view since many fabrication techniques need sophisticated instrumentation, skilled personnel, purity of chemicals, specificity of the medium, controlled atmosphere, etc. and are anticipated for lab-scale production. The electrospinning process is an exception, which can address all the former problems associated with other fabrication techniques. This chapter covers the electrospun ceramic nanofibers such as oxides, carbides, nitrides, sulfides, etc. from various precursors and their application in the field of biomedical engineering, filtration, energy, electronics, sensor, catalysis, etc. and their peculiar properties, such as photoluminescence, thermoelectric, piezoelectric, and magnetic. Nevertheless, the application of ceramic nanofibers, far more than what is discussed here, and advanced studies are essential to explore the applications of ceramic nanofibers in numerous untouched areas where conventional materials can be replaced. © 2021 Elsevier Ltd All rights reserved.Item Electrospun PVDF-based composite nanofabrics: An emerging trend toward energy harvesting(Elsevier, 2021) Shetty, S.; Anandhan, S.Poly(vinylidene fluoride) (PVDF) has gained attention in energy-related applications, due to its ferroelectric, piezoelectric, and pyroelectric properties. PVDF is a semicrystalline fluoropolymer having different phase domains based on its chain conformations. The polar domains contribute to its ferroelectric and piezoelectric characteristics. Electrospinning is a facile nanofabrication technique used to produce ultrafine fibers that self-integrates into functional webs/nanofabrics. This chapter emphasizes the electrospinning/filler route to tune the electroactive properties of PVDF-based composite nanofabrics and their applicabilities toward energy-related systems. The influence of various fillers/additives on the structure, morphology, and electroactive response of PVDF composite nanofabrics, including their incorporation into energy-related systems, is described in detail. Understanding the interplay between the filler and PVDF matrix coupled with electrospinning could contribute toward the fabrication of scalable and practical energy systems. © 2021 Elsevier Inc.Item Fly ash-reinforced poly(vinyl alcohol) composites(Elsevier, 2021) Anandhan, S.; SelvaKumar, S.; Patil, A.G.Fly ash (FA) is a waste residue and huge amounts of it have been produced from coal-fired power plants. As a result, it has become a serious issue and there is an urgent need to reduce its accretion as well as improve the safe disposal of FA as it has many toxic constituents including lead, arsenic, and chromium. In an effort to utilize FA, it has been widely used as filler for fabricating polymer composites to improve their performance. Recently, FA-incorporated polymers have received the attention of researchers and industries due to their remarkable properties, such as improved mechanical strength without sacrificing their elasticity, thermal, flame resistance, wettability, resistance to hydrolysis, and possessing excellent dynamic mechanical properties even at low temperatures. In comparison with conventional FA-based polymer composites, those based on surface-modified FA and nanostructured FA (NFA) exhibit superior mechanical and technical properties. The present article reviews various aspects of poly(vinyl alcohol)/FA-based composites. It also focuses on the effect of particle size reduction of FA on the physicochemical properties of poly(vinyl alcohol)/NFA composites. © 2022 Elsevier Inc. All rights reserved.Item Graphene-based elastomer nanocomposites: A fascinating material for flexible sensors in health monitoring(CRC Press, 2022) Khalifa, M.; SelvaKumar, S.; Anandhan, S.[No abstract available]Item Polymer Electrolytes and Separators for Magnesium-Ion Batteries(CRC Press, 2024) Singh, R.; Khalifa, M.; Janakiraman, S.; Adyam, V.; Anandhan, S.; Biswas, K.Magnesium (Mg)-ion-based rechargeable batteries are attractive because magnesium is bivalent, abundant, non-toxic, and inexpensive. In the development of Mg-ion batteries (MIBs) with high energy densities, their ionic conductivity and safety have become important features. The most commonly used cathodes are Mo6S8, MoO3, V2O5, MnO2, and TiO2, but they are limited due to low voltages (<2.0 V) and low specific capacities. Therefore, electrolytes are needed to improve the voltage stability and ease of synthesis. In this chapter, polymer electrolytes and separators in MIBs with liquid or gel electrolytes are briefly outlined. Polymer electrolytes are classified into two categories, namely solid polymer electrolytes and gel polymer electrolytes (GPEs). Solid polymer electrolytes have several advantages such as high safety, lightweight, and favorable mechanical properties, but their weakness is their relatively lower ionic conductivity. To overcome these issues, GPE, which is a combination of liquid electrolyte and a polymer matrix, is explored. Poly(vinylidene fluoride)-based gel electrolytes showed a high ionic conductivity of the order of 10−3 S cm−1 at room temperature. In GPEs, an electrolyte is used as an ion transport medium between the electrodes, whereas a polymer membrane acts as a separator, thereby eliminating the physical contact between the electrodes. © 2025 selection and editorial matter, Prasanth Raghavan, Akhila Das, and Jabeen Fatima M. J.Item Rubber-based lightweight nanocomposites: spectroscopic characterization(Elsevier, 2025) Khalifa, M.; Anandhan, S.Carbon nanofiller-based rubber nanocomposites have gained considerable attention in academia and industries because of their suitability in various applications, including automobiles, sports, aerospace, medical, and structural components. The addition of carbon nanofillers, such as carbon nanotubes, graphene, carbon fibers, carbon black, and graphite, helps in tuning the electrical conductivity, thermal conductivity, barrier properties, and mechanical properties of rubbers. Some of these characteristics and properties of rubber nanocomposites can be studied using spectroscopic techniques. These techniques are rapid, nondestructive, highly sensitive, and provide molecular-level information. Various spectroscopic techniques, such as Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), etc., have been adopted that provide information on the dispersion of fillers, interfacial interactions, molecular bonds, orientations, elemental compositions, impurities, etc. This chapter provides an overview of the use of FTIR, Raman, XPS, and NMR spectroscopies in the characterization and analysis of carbon nanofiller-rubber composites. © 2026 Elsevier Inc. All rights reserved..Item Piezoelectric and triboelectric nanogenerators based on electrospun PVDF-nanofiller composites(Institute of Physics Publishing, 2025) Sathies, T.; Ekbote, G.S.; Anandhan, S.[No abstract available]Item Solubility Limits of Ceria-Zirconia-Lanthana Solid-Solutions(Elsevier Ltd, 2017) Abbas, Z.; Surendran, M.; Anjana, P.A.; Jidev, P.K.; Harshini, H.; Sudhakar Naidu, N.; Anandhan, S.; Bhat, K.U.; Bhaskar Babu, G.U.; Prasad Dasari, H.P.We demonstrate, the solubility limits of Ceria-Zirconia-Lanthana (CZLa) solid-solutions with the increase in heat-treatment temperature from 600°C to 1300°C. CZLa nano-crystalline samples were successfully synthesized by EDTA-Citrate complex method and were characterized by Raman Spectroscopy (RS) and Transmission Electron Microscopy (TEM) analysis. With an increase in temperature, it is noticed that the solubility limit is decreased in CZLa system. At 600°C, a very good solubility is observed in CZLa system and is confirmed from RS analysis. At higher heat-treatment temperatures (1000 and 1300°C), with an increase in La content, Zr precipitated in the CZLa system and is confirmed from RS analysis. The reason for such kind of behavior in this CZLa system is clearly explained in this work. © 2017 Elsevier Ltd.Item Dispersion analysis of nanofillers and its relationship to the properties of the nanocomposites(Elsevier Ltd, 2021) George, G.; Dev, A.P.; Asok, N.N.; Anoop, M.S.; Anandhan, S.The dispersion and distribution characteristics of the reinforcements are the key reasons that influence the mechanical properties of the nanocomposites. In this paper, the dispersion and distribution analysis of nanofillers in a representative polymer is performed and the results are correlated to the crystalline and mechanical properties of the nanocomposite. The nanocomposite used in the present study is Elvaloy®4924 (EVACO)/halloysite nanotubes (HNTs) composite. The dispersion of halloysite nanotubes in the EVACO matrix is recorded as aluminum elemental maps obtained from energy dispersive spectroscopy (EDS). The dispersion and distribution of fillers in the composite are quantified using an image processing technique and it is correlated to the crystalline and tensile properties of the composites. The better dispersion and distribution of HNTs at 1wt.% filler loading resulted in a remarkable improvement in the crystallinity of the composite, which is measured by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The tensile strength was highest for composites loaded with 1 wt.% filler, and the strength decayed as the loading was further increased. Agglomeration of halloysite nanotubes and polymer-filler debonding was the major reason behind the reduction in tensile strength with filler loading, as observed in the scanning electron micrographs of the fractured surfaces. © 2021 Elsevier Ltd. All rights reserved.