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-Fe۲O۳) nanoparticles were prepared by solution casting method. The effect of g-Fe۲O۳ 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-Fe۲O۳ nanoparticles. Among the composites Cs-۲۰% graphite - ۲۰% g-Fe۲O۳ has dielectric constant of ~۱۶.۵ at ۱ 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-Fe۲O۳ nanoparticles, and the value is found to be ۵.۷x۱۰-۶ S/cm. Various parameters such as dielectric constant, dielectric loss, electric modulus, conductivity, activation energy were analyzed. Magnetic measurement of g-Fe۲O۳ 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.

کلیدواژه ها:

Chitosan ، Graphite ، maghemite nanoparticles ، Superparamagnetism