Low-dielectric-constant cross-linking polymers:: Film electrets with excellent charge stability

The cross-linking low-dielectric-constant polymers benzocyclobutene (BCB) and perfluorocyclobutene (PFCB) are identified as film electrets with excellent charge stability, comparable to the members of the polytetrafluoroethylene family. BCB and PFCB films can be easily prepared on substrates by spin coating. The onset of molecular motion at the high- and low-temperature glass-like transitions is revealed by dielectric dilatometry. BCB and PFCB electret films exhibit remarkable stability regarding both negative and positive charging. They enlarge the family of charge electrets and may thus become interesting for miniaturized electret devices. (C) 1999 American Institute of Physics. [S0003-6951(99)02951-4].