Molecular Ferroelectrics as Chemically Driven Energetics*

This work designs and explores energetic molecular ferroelectrics using imidazolium perchlorate (ImClO₄) as an example. The material integrates uniquely the covalent bond energetic imidazolium cations as fuel and the perchlorate anions as oxidizer with spontaneous polarization in one molecular crystal. Changes in the structure, composition and energetic properties were studied as function of polarization through thermal heating. High-resolution transmission electron micrographs prior to heating showed distinct moiré fringes revealed self-polarization induced ferroelectric domains. Low temperature heating at 150 °C led to depolarization and desorption of the imidazole rings with significant morphological changes in the crystal without significant influence in the microsecond-timescale energy release. Higher temperature pyrolysis at 350 °C produced a large exotherm and gas combustion products including H₂O, CO/N₂, and CO₂. Via the laboratory-scale energetic test technique - laser-induced air shock from energetic materials (LASEM), the detonation velocity of ImClO₄ was estimated at 7.2 ± 0.27 km/s, which is comparable to military explosives 2,4,6-trinitrotoluene (TNT) and hexanitrostilbene (HNS). The electron-phonon interactions were also demonstrated by polarization-dependent heat transfer and specific power. These results unvail the potential of a new class of molecular ferroelectrics for energetic applications.