Dielectric properties of flexible NanoCellulosic films with embeded Graphene Oxide (GO) nanoplatelets Used in electronics as cost-effective, green and flexible, thus suitable alternative for energy storage devices. Yasir Beeran1,2, Vid Bobnar3, Sabu Thomas1, Vanja Kokol1 1University of Maribor, Institute for Engineering Materials and Design, Maribor, Slovenia; 2Mahatma Gandhi University, International and International University Centre for Nanoscience and Nanotechnology, Kottayam, India; 3Jožef Stefan Institute, Condensed Matter Physics Department, Ljubljana, Slovenia. vanja.kokol@um.si

CNF-NGO films prepared by solvent casting Cellulose Nano-Fibrils (CNF) vs. TEMPO-CNF: few m long with a dimension of 5−20 nm, low density, high strength. Nitrogen-doped Graphene Oxide (NGO) with planar structure and abundant oxygen-containing functional groups. & CNF NGO-0.5% NGO-1% NGO-1.5% NGO-2% NGO-3%

Thermo-mechanical properties CNF TCNF C-NGO: 3% T-NGO: 3% The addition of NGO to CNF/TCNF matrix: increased Young’s modulus (25%, to 60-75 MPa) and Tensile strength (33%, to 1500-2050 MPa) and enhanced the thermal stability.

CNF-GO films casted & UV-irradiated under N2 Un-treated 5h UV-irradiated CGO: 3% TGO: 3% high Storage modulus (to 14-30 GPa) and low Loss modulus (to 400-700 MPa) at 25°C with increased thermal stability without using of any toxic chemicals.

Dieletric properties: constant () & conductivity () CNF-NGO at 1 MHz CNF-GO at 1 MHz 5h UV-irradiated The dielectric properties at high frequency region (1 MHz) show significant enhancement (Ɛl of 50-60) than reported studies for TCNF-NGO films, being even higher (Ɛl of 100-120) using UV-irradiated TCNF-GO.