Huge improvements of electrical conduction and dielectric breakdown in polyimide/BN nanocomposites

• Published in: IEEE transactions on dielectrics and electrical insulation Vol. 23; no. 5; pp. 2795 - 2803
• Main Authors: Diaham, S., Saysouk, F., Locatelli, M.-L, Lebey, T.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: BN nanofillers; Boron nitride; Conductivity; Current measurement; Dielectric breakdown; dielectric strength; Electric fields; Electrical conduction; Engineering Sciences; High temperature; ionic hopping; Nanocomposites; nanodielectrics; Polyimide; Space charge; Temperature; Temperature measurement; Polyimide; Dielectric strength; Nanocomposites; Nanodielectrics; BN nanofillers; Ionic hopping; Boron nitride; Electrical conduction
• ISSN: 1070-9878; 1558-4135
• DOI: 10.1109/TDEI.2016.7736839

The electrical conduction and dielectric breakdown of polyimide/boron nitride (PI/BN) are investigated in a large temperature range up to 350 °C. This work shows that BN nanofillers act as deep traps for mobile ions. Below 150 °C, the nanostructuration of PI slightly improves the DC conductivity and the breakdown field. On the contrary above 150 °C, while neat PI exhibits ionic space charge contribution on the charging currents, PI/BN nanocomposites show a return to normal polarization currents. In such combined high field and high temperature ranges, the nanostructuration of PI allows increasing the mean free path of ions by decreasing the ionic hopping distance. The consequence of the improvement of the total trap density is a huge decrease (5 orders of magnitude) in the steady state currents and an increase (factor 2) in the breakdown field of PI/BN. This study proves the possibility to extend both the electric field and temperature ranges of PI films thanks to an adequate nanostructuration.