chitosan – graphite – maghemite – a flexible, superparamagnetic nanocomposite comprising of microcapacitors

In this work, an eco-friendly “green” nanocomposite of chitosan containing graphite and maghemite (g-fe2o3) nanoparticles were prepared by solution casting method. the effect of g-fe2o3 nanoparticles on structural, electric and dielectric properties of chitosan-graphite (cs-graphite) composites was investigated. the dielectric constant of cs-graphite composites increased with incorporation of g-fe2o3 nanoparticles. among the composites cs-20% graphite - 20% g-fe2o3 has dielectric constant of ~16.5 at 1 mhz at room temperature. with increase in temperature the dielectric constant varied significantly. the conductivity of cs-graphite is enhanced by one order of magnitude with addition of g-fe2o3 nanoparticles, and the value is found to be 5.7x10-6 s/cm. various parameters such as dielectric constant, dielectric loss, electric modulus, conductivity, activation energy were analyzed. magnetic measurement of g-fe2o3 nanoparticles and the pncs showed superparamagnetic behaviour. a model is proposed to explain the observed dielectric behavior of polymer nanocomposites (pncs). the formation of microcapacitors by incorporation of maghemite nanoparticles between graphite is proposed.