Some applications of organic microcrystals

As described in the preceding chapter, the most striking characteristic of the reprecipitation method is that organic microcrystals prepared are stable when dispersed in a medium, owing to high ζ-potential. Hence, the optically transparent and layered thin films could be fabricated by electrostatically adsorbing poly(DCHD) microcrystals with negative ζ-potential on an inert polycation film, and the χ⁽³⁾(ω) values were enhanced mainly by concentration effect. In addition, SHG-active DAST microcrystals, having huge dipole moment, dispersed in hydrocarbon medium were oriented by applying remarkably lower electrostatic field, compared with DC field in ordinary liquid crystal molecules. The present microcrystal dispersions can be regarded as a novel "Liquid and Crystals" system.