Vol.:(0123456789) 1 3 Journal of Inorganic and Organometallic Polymers and Materials https://doi.org/10.1007/s10904-018-1016-3 Optical, Dielectric Properties and Energy Storage Efciency of ZnO/ Epoxy Nanocomposites Wissal Jilani 1,2  · Najla Fourati 3  · Chouki Zerrouki 3  · Olivier Gallot‑Lavallée 4  · Hajer Guermazi 2 Received: 1 September 2018 / Accepted: 30 October 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract ZnO/epoxy nanocomposites were prepared in fve diferent contents (0.25–3.0 wt%). Optical, thermal and dielectric prop- erties have been examined as a function of ZnO nanoparticles. The absorption optical spectra exhibit a broad intense peak assigned to the n–π* (HOMO–LUMO) transitions. Nanocomposite with 3.0 wt% ZnO sample completely blocks UV-light radiations in the region from 300 to 480 nm, which allowed that the prepared material to be used for UV-Shielding devices. The optical band gap is found to decrease with increasing fller ZnO concentrations. This might be due to increasing the density of defect states. Permittivity and electric modulus formalisms are used to analyze and interpret the experimental data. γ relaxation is observed in the low temperature region, which is attributed to the rearrangement of small parts of the polymeric chains. The α relaxation and the Maxwell–Wagner–Sillars (MWS) efect, attributed to the glass rubber transition of the polymeric matrix and the interfacial polarization phenomena respectively, are observed in the high temperature region. Using Havriliak–Negami approach, the temperature dependence of relaxation time for MWS and γ relaxations follows an Arrhenius behavior while the α relaxation time is well described by the Vogel–Fulcher–Tamann behavior. The activation energies of all relaxation modes were calculated and discussed. The energy density of the investigated samples is signifcantly enhanced. It is about 2 × 10 −6  J/m 3 for nanocomposite with 3.0 wt% ZnO at 20 °C. These results indicate that the efect of ZnO nanoparticles makes the proposed materials suitable candidates for energy storage applications. Keywords ZnO/epoxy nanocomposites · Dielectric properties · Optical properties · Energy storage 1 Introduction In recent years, hybrid polymer nanocomposites have been receiving great interest due to their wide range of appli- cations in optical devices which finds many promising enhancements in polymer properties and extending their utility [1–5]. Sinha et al. [6] found that the impregnation of several inorganic compounds (i.e. nanoparticles) into a polymer matrix has a remarkable infuence on its advanced optical and electrical properties. Composite systems have diferent felds applications as well as the electromagnetic shielding material [7], the electrostatic dissipation [8] and charge storage capacitors [9]. An epoxy resin is a class of thermosetting polymers. Epoxy polymers are widely used as suitable matrices because they ofer versatility, low shrink- age, chemical resistance and outstanding adhesion [10–12]. Besides their most applications in modern technology as well as electrical machinery, power electronic devices, pack- ing of integrated circuits, electronic, wear resistance and light-emitting diode (LED) and wonderful electrical per- formance [13]. The compound semiconducting materials (e.g., CaCO 3, TiO 2 , Cu doped ZnO and ZnO, etc.) have attracted research interest due to their unique electrical and optical properties and have opened many opportunities for electronic and opto- electronic devices [14–16]. Moreover, adding materials such * Wissal Jilani jilaniwissal@yahoo.fr 1 Department of Physics, Faculty of Science Sciences and Arts Dhahran Al Janoub, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia 2 Unity of Physics of Insulating and Semi-Insulating Materials, Faculty of Sciences of Sfax, University of Sfax, B.P. 1171, 3000 Sfax, Tunisia 3 SATIE, UMR 8029, CNRS, ENS Cachan, Cnam, 292 rue Saint Martin, 75003 Paris, France 4 Grenoble Electrical Engineering Laboratory (G2ELab), Grenoble University Alpes & CNRS (UGA), Grenoble, France