Charge behavior at interfaces involving nanocomposites

Abstract

A major disadvantage of polymeric insulation is space charge accumulation at high dc electric fields. Space charge is associated with degradation and premature failure of polymeric insulation through distortion of electric fields. Polymer nanocomposites or nanodielectrics have emerged as a class of novel dielectric materials with improved material properties. We are therefore, looking at an increased use of nanocomposites in the near future. Additionally, we expect nanocomposites to be used in conjunction with conventional insulating materials, thus giving rise to interfaces. Interfaces are important because they often cause accumulation of interfacial charge or space charge with its attendant issues. The present work studies space charge behavior in nanocomposites and its interfaces with other materials. The space charge distribution is mapped using a Pulsed Electro-Acoustic (PEA) system. Polarization-depolarization current measurements are also performed. Measurements are performed under different experimental conditions (electric field, aging etc.). Experimental data indicate that nanoparticles affect charge injection as well as charge transport through change in interfacial and bulk properties. Further, thermal aging causes significant increase in charge injection and charge transport through the material. Experiments with as-received and surface-treated nanoparticles indicate that surface treatment affects the interphase significantly.