Poled polymers for sensors and photonic applications

A brief survey of the electrical and optical properties of poled polymer electrets for sensors and photonic applications is given. Semicrystalline ferroelectric polymers are highly suitable for piezo- and pyroelectric applications, while amorphous polymers containing molecular dipoles with acceptor and donor groups linked by delocalized pi electrons (A-pi-D) are interesting for photonic applications. The large variety of poling techniques, such as electrode, corona, electron-beam, and photothermal poling, is discussed in detail together with specifically developed poling techniques for ferroelectric or amorphous polymers. Methods for the experimental investigation of the polar order are based on the piezo-, and pyroelectric effect, birefringence, the electro-optical effect and second-harmonic generation. Newly developed thermal analysis techniques and dipole relaxation spectroscopies complement traditional techniques, such as thermally stimulated depolarization and broadband linear and nonlinear dielectric relaxation spectroscopy. The compatibility of polymers with semiconductor technology is illustrated with selected applications in hybrid integrated thermal and acoustical imaging devices, electro-optical modulators and second-harmonic generators. (C) 1996 American Institute of Physics.