Browsing by Author "Madhukar, B.S."

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    Incorporation of graphite into iron decorated polypyrrole for dielectric and EMI shielding applications
    (Elsevier Ltd, 2020) Madhusudhan, C.K.; Mahendra, K.; Madhukar, B.S.; Somesh, T.E.; Faisal, M.
    Synthesis of polypyrrole (PPy) / graphite (G) composites via chemical oxidation polymerization method is reported. Synthesized composites were studied for its structural, optical and electrical properties. Structural and morphological studies were performed using powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and the effect of graphite on the properties of PPy is elaborated in detail. Further, the electrical measurements were carried using dielectric analyzer. Dielectric behavior of the composites was also compared with the PPy and graphite and confirmed the dependency of graphite on PPy/graphite nanocomposites. The EMI shielding response of PPy/graphite nanocomposites were measured in the microwave frequency range from 12 to 18 GHz (Ku band), of practical relevance. The observed effective electrical and EMI shielding properties highlights the prospects of multifunctional applications of these PPy/graphite nanocomposites. © 2020 Elsevier B.V.
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    Multifunctional Polypyrrole/Multi-Walled Carbon Nanotube Composite Material: Dielectric, Humidity Sensing and Broadband EMI Shielding Properties
    (Pleiades journals, 2021) Madhusudhan, C.K.; Mahendra, K.; Madhukar, B.S.; Somesh, T.E.; Faisal, M.
    Abstract: Conducting polymer composites with suitable combination of two components in nanoscale are expected to facilitate wider applications of composites. In this study, polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT) nanocomposites prepared by in situ chemical oxidative polymerization were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV–Vis spectroscopy. The electrical and dielectric properties were investigated using complex impedance technique. Complex dielectric permittivity, complex electric modulus and complex impedance variations were studied in the frequency range of 10 Hz–1 MHz. The dielectric attributes and conductivity data of different nanocomposites analyzed as a function of frequency revealed that the incorporation of MWCNT phase into polypyrrole matrix affects the electrical and dielectric properties of the composites. Humidity sensor measurements show that PPy/MWCNT can be effectively optimized as candidate for humidity detection. The nanocomposites were also studied for broadband EMI shielding applications by characterizing the materials in the 12?18 GHz (Ku band) to understand the shielding properties. The absorption dominant shielding effectiveness (SE) observed in the range of ?13 to ?15 dB was stable with visible variation with varying concentration of MWCNT in PPy. The experimental results of dielectric characterization, humidity sensing and EMI shielding response reveal that PPy/MWCNT composite can be suitable multifunctional material for various applications. © 2021, Pleiades Publishing, Ltd.