Electric-field induced phase separation and dielectric breakdown in leaky dielectric mixtures: Thermodynamics and kinetics

Dielectric materials form the foundation of many electronic devices. When connected to a circuit, these materials undergo changes in microscopic morphology, such as the demixing of dielectric mixtures through phase separation and dielectric breakdown, resulting in the formation of micro-filaments. Consequently, the macroscopic properties and lifespan of the devices are significantly altered. To comprehend the physical mechanisms behind it, we conducted a systematic investigation of the thermodynamics of multicomponent leaky dielectric materials. Beginning with the total energy functional, we derived expressions for the binodal composition, spinodal composition, and critical points. Furthermore, we constructed and validated theoretical phase diagrams for the binary leaky dielectric mixture, incorporating three crucial freedoms: composition, temperature, and electric field strength. In addition, we analyzed the equilibrium interfacial tension impacted by the electric field and studied the dynamic aspects of dielectric materials, examining two morphological transformations: electrostriction and dielectric breakdowns. Our analysis unveiled a connection between these dynamic phenomena and the electric field-induced interfacial instability. The present work is expected to be supportive of future research on multicomponent dielectric materials by offering a comprehensive understanding of their thermodynamic and kinetic behaviors.