Synthesis of perfluoroalkylated azo dyes and their application to guest-host liquid crystal display

Abstract

A series of novel dis- and trisazo dyes containing a perfluoroalkyl, perfluoroalkylthio and perfluoroalkylsulphonyl groups have been synthesized. The absorption bands of these dyes were more bathochromic than the corresponding alkyl derivatives. The solubility of disazo dyes containing perfluoroalkyl and perfluoroalkylthio groups in hexane was larger than the alkyl derivatives. To obtain good dichroism, the azo dyes were required to have a large l/d ratio (>2.50). These novel azo compounds could be used practically as dichroic dyes in guest-host liquid crystal displays.