Hydrogen‐bonded liquid crystals derived from supramolecular complexes of pyridylated poly(propyleneimine) dendrimers and a cholesterol‐based carboxylic acid

Diaminobutane poly(propyleneimine) dendrimers of second to fifth generations were functionalized by the introduction of pyridyl moieties at their primary amino groups through their interaction with 3‐pyridyl isothiocyanate. These pyridylated diaminobutane poly (propyleneimine) dendrimers were subsequently mixed with 3‐cholesteryloxycarbonylpropanoic acid to form the corresponding hydrogen‐bonded supramolecular complexes. The materials obtained exhibit smectic A phases over a relatively broad temperature range from about 60°C to 140°C. Within the smectic layer the cholesteryl moieties are almost orthogonal above and below to the dendrimeric portion of the molecule. On cooling, the materials form liquid crystalline glasses which retain the structural characteristics of the smectic A phase.