Induced smectic-B and smectic-G phases in hydrogen-bonded complexes (nOBA:PFOA): thermal and phase behaviour studies

A new series of intermolecular hydrogen-bonded liquid crystals are synthesised. The hydrogen bond formed between the mesogenic p-n-alkoxy benzoic acids (nOBAs) and non-mesogenic perfluorooctanoic acid (PFOA) (where n represents the alkoxy carbon numbers from 4 to 12 and 16). The IR spectral investigation confirms the hydrogen bond. The thermal and phase behaviour of these materials were studied by the use of polarising thermal microscope attached with a hot stage and the differential scanning calorimeter. From the experimental observations, both smectic-B and smectic-G phases are induced in the complexes having the chain number n = 7–12 by quenching smectic-C phase.