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The present work has been carried out to evaluate the dielectric properties and ac-electrical conductivity of cellulose nanofibers. The cellulose nanofibers (CNF) described in this work are the ones extracted from cotton via a simple acid hydrolysis method and are characterized with X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV-Visible diffuse reflectance spectroscopy. The optical band gap of CNF found out using the Kubelka-Munk plot is 3.30 eV. The dielectric constant, dielectric loss, and ac-electrical conductivity of the prepared CNF have been investigated in the temperature range from 30 °C to 300 °C and in the frequency range from 50 Hz to 5 MHz. The synthesized system exhibits a higher dielectric constant value for all temperatures in the low-frequency (0.1 kHz) region and a frequency-independent behavior above 10 kHz. In the high-frequency region, the dielectric constant is independent of temperature. Also, the study shows that the conductivity increases with increasing frequency and temperature. The maximum values of ac-conductivity at room temperature (30 °C) and high temperature (300 °C) are found to be 4.58 9 10 -5 S/cm and 2.26 9 10 -4 S/cm, respectively. In brief, the studies point to the application potential of CNF for future flexible electronics.

Copper(II) complexes of two biologically important ligands, viz., embelin (2,5-dihydroxy-3-undecyl-2,5-cyclohexadien 1,4-dione) and 2-aminobenzimidazole were entrapped in the cages of zeolite Y by the flexible ligand method. The capability of these compounds in catalyzing the reduction of oxygen (industrially known as deoxo reaction) was explored and the results indicate an enhancement of the catalytic properties from that of the simple copper ion exchanged zeolite. These point to the ability of the ligands in enhancing the oxygen binding capability of the metal ion. Elemental analyses, Fourier transform infrared (FTIR), diffuse reflectance and EPR spectral studies, magnetic susceptibility measurements, TG, surface area analyses and powder X-ray diffraction studies were used in understanding the presence, composition and structure of the complexes inside the cages. The study also reveals the increased thermal and mechanical stability of the complexes as a result of encapsulation.