Molecular modeling of polymers for high energy storage capacitor applications

Polymer-based capacitors with higher voltage and higher energy density limits than currently available are possible if dielectric constants can be increased without compromising thermal and mechanical properties or the ability to clear defect sites. A molecular modeling approach is described which has the goal of designing a modified glassy (poly)etherimide polymer with a bulk dielectric constant several times larger than the parent resin. Segment-level dipole moments are predicted using ab initio and semiempirical quantum mechanical self-consistent field methods, and torsional-rotational mobility is estimated using force-field calculations to evaluate intramolecular and intermolecular energy barriers. Finally, bulk dielectric constants are calculated from the Onsager-Kirkwood equation for amorphous systems