AC ELECTRIC-FIELD-INDUCED ORIENTATION OF POLAR ORGANIC NANOCRYSTAL IN DISPERSE SYSTEM

Monodispersed DAST nanocrystals have almost been successfully fabricated by means of the inverse reprecipitation method. By employing AC electric field, high electric field of above ca. 1.0 kVcm -1 could be applied to polar DAST nanocrystals dispersed in decahydronaphthalene, so as to avoid electrophoresis of nanocrystals under DC electric field. The response of DAST nanocrystal dispersion to applied AC electric field was analyzed phenomenologically by fitting Langevin function, which provided a large permanent dipole moment of DAST nanocrystal. In addition, we have succeeded in in situ observation of AC electric-field-induced orientational motion of DAST crystals by using an optical microscope. The present DAST nanocrystal dispersion system will be expected as an optical device like display monitor.