A self-assembled, nacre-mimetic, nano-laminar structure as a superior charge dissipation coating on insulators for HVDC gas-insulated systems

Abstract

Nacre is well-known for its unique properties due to its “bricks-and-mortar” structure. We employed this biological paradigm to fabricate nano-laminar coatings with controlled arrangement of montmorillonite (MMT) nanoclay sheets and polyvinyl alcohol (PVA) polymer binders by a self-assembly process. The abundant inorganic/organic interfaces were demonstrated to play critical roles in enhancing charge dissipation laterally on the insulator surface, so that the surface charge accumulation is suppressed under dc stress. Moreover, the stacking barriers help to protect insulator surfaces from hot electron bombardment, inhibiting further electron avalanche. In this manner, the flashover strength of the insulator is improved by 18%. This strategy is practical and scalable, allowing for industrial applications.