Photoresponsive behavior of hydrophilic/hydrophobic-based novel azobenzene mesogens: synthesis, characterization and their application in optical storage devices.

Three series of alkoxy chain-bearing azobenzene-derived quaternary ammonium iodides with an alkoxy chain at one end, namely ,-diethanol-6-(4-((4'-alkyloxyphenyl)diazenyl)phenoxy)hexan-1-ammonium iodides, -ethyl--ethanol-6-(4-((4'-alkyloxyphenyl)diazenyl)phenoxy)hexan-1-ammonium iodides and ,-diethyl-6-(4-((4'-alkyloxyphenyl)diazenyl)phenoxy)hexan-1-ammonium iodides were synthesized and characterized. Their mesomorphic and photoswitching properties were examined polarising optical microscopy (POM), differential scanning calorimetry (DSC) and UV-vis spectrophotometry. The liquid crystalline tilted schlieren texture of smectic C, non-tilted natural focal conic texture of smectic A and smectic B phases were observed in the ,-diethanol- and -ethyl--ethanol-bearing ammonium group substituted at the terminal the alkoxy chain of the azo moiety.