This invention provides
electrically conductive electret,
electret-based direct-current power source and structural
electret, with applications including the self-sensing of damage, stress and strain (including structural self-sensing) and electric powering (including structural self-powering). The electret is an
electrically conductive material comprising
mobile charge carriers (electrons, holes or ions), which exhibit a gradient in the carrier concertation along a line connecting the positive charge center and
negative charge center in the electret. The carriers create an electric
dipole. The material is electrically continuous along this line, which is along the path of least electrical resistance. The material exhibits
microstructure comprising microscopic features that are positioned along said line and that interact with said carriers, with the interaction enhancing said
dipole. The materials are preferably metals, carbons and their composites. The electret's
electric field preferably ranges from 10′ V / m to 1 V / m. The electrical
conductivity preferably ranges from 103Ω−1·m−1 to 108Ω−1·m−1.