Interfacial polarization suppression of P(VDF-HFP) film through 2D montmorillonite nanosheets coating

Polymer based dielectrics with excellent high electric field withstanding capability are of great significance for enhancing the power density and payload efficiency for both electrical and electronic systems. However, polymer-metal interface is prone to defect formation, leading to the dielectric aging and the initialization of electrical breakdown failure. A facile Montmorillonite (MMT) coating is self-co-assembled on the surface of P(VDF-HFP) high-k film to form hundreds of 2D nanosheets layers to impede the charge injection over the metal-polymer interface. The MMT coating increases the breakdown strength of the P(VDF-HFP) co-polymer film from 405 to 452 MV/m. The high field conduction study reveals a highly enhanced Schottky injection barrier that blocks the charge injection from electrodes to polymer bulk, leading to significantly suppressed charge injection and conduction loss in polymer. In addition, the introduction of MMT layered coating leads to prominent suppression of interfacial polarization loss, a phenomenon known as the blocking capacitance, which would otherwise stem from the accumulated charges of polymer-metal interface, by one order of magnitude, as demonstrated by the dielectric response analysis by using the Dissado-Hill model over a broad range of temperature and frequency. The superior charge injection and interfacial polarization suppression via the application of MMT coating impart the P(VDF-HFP) co-polymer film with higher breakdown strength, and provides an effective approach to develop high performance polymer dielectrics by interfacial engineering. This work provides insights into the understanding of the enhancement mechanism of 2D coating.