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MnO 2 ‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction
Author(s) -
Pal Rishi,
Goyal Sneh Lata,
Gupta Vinay,
Rawal Ishpal
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201901199
Subject(s) - materials science , polyaniline , electromagnetic shielding , variable range hopping , composite material , composite number , electrical resistivity and conductivity , emi , thermal conduction , analytical chemistry (journal) , electromagnetic interference , electronic engineering , polymer , chemistry , polymerization , electrical engineering , chromatography , engineering
Abstract The core‐shell structured based Polyaniline/MnO 2 composites were synthesized by chemical oxidation method, wherein MnO 2 particles acts as a magnetic core while polyaniline chains wrapped over these particles acts as a shell. Four different loading concentrations of MnO 2 particles ( 10, 20, 30 and 40 wt %) were used to investigate the effect of MnO 2 concentration on the EMI shielding effectiveness. X‐ray diffraction (XRD) studies performed on pristine MnO 2 and composite samples reveal the polycrystalline nature of the MnO 2 particles and semi‐crystalline nature of the composites with a sharp peak around 25° over a broad hump. Vibrating sample magnetometry (VSM) studies performed on the pristine MnO 2 particles as well composite sample (S4) at higher loading ( 40 wt %) concentration of MnO 2 suggest the ferromagnetic nature at room temperature. The charge transport properties of the prepared samples have been investigated under variable range hopping (VRH) conduction. Mott's three dimensional VRH model has been found to be applicable for conduction in the present samples. The dc conductivity of the prepared samples is found to increase with MnO 2 loading concentrations, which suggest their possible validity for EMI shielding applications. Therefore, the prepared samples are analyzed for EMI shielding properties in the frequency range of 8.2 to 12.4 GHz (X‐band). The sample prepared with 30 wt% of MnO 2 has as much as 50 dB shielding effectiveness, which is quite higher than that required for industrial application (∼ 30 dB).