Asheesh Kumar

An asymmetric electrically conducting self-aligned graphene/polymer composite thin film for efficient electromagnetic interference shielding

Here, we study the self-aligned asymmetric electrically conductive composite thin film prepared via casting of graphene oxide (GO)/poly (vinylidene-hexafluoropropylene) (PVDF-HFP) dispersion, followed by low temperature hydriodic acid reduction. The results showed that composite thin film revealed the high orientation of graphene sheets along the direction of film surface. However, graphene sheets are asymmetrically distributed along the film thickness direction in the composite film. Both sides of as prepared composite film showed different surface characteristics. The asymmetric surface properties of composite film induced distinction of surface resistivity response; top surface resistivity (21 Ohm) is ∼ 4 times higher than bottom surface resistivity (5 Ohm). This asymmetric highly electrically conducting composite film revealed efficient electromagnetic interference (EMI) shielding effectiveness of ∼ 30 dB. This study could be crucial for achieving aligned asymmetric composite thin film for high-perfor...

Structural and Mössbauer spectroscopic study of cubic phase hydrogen storage alloys Ti2Nb1−xFex

The cubic phase alloys Ti2Nb1−xFex (x = 0.0, 0.4, 0.6) have been prepared by an arc melting method. The crystal structure and hyperfine interactions have been carried out using X-ray diffraction and Mossbauer spectroscopy, respectively. Room temperature 57Fe Mossbauer spectra could be fitted with one doublet and four doublets for the alloys and their hydrides, respectively. The hydrogen absorption capacity increases with increase in Fe substitution.