Supramolecular liquid-crystalline polyurethane

A novel supramolecular liquid-crystalline polyurethane was prepared by mixi ng the polyurethane containing a pendant pyridyl unit as H-bond acceptor an d 4-dodecyloxybenzoic acid as H-bond donor. Intermolecular hydrogen bond fo rmation was confirmed by Fourier transform infrared spectroscopy. The liqui d-crystalline behaviour of the complex formed was established by differenti al scanning calorimetry, polarizing optical microscopy and X-ray diffractom etry. The complex exhibited highly ordered smectic and nematic phases. The smectic-nematic and nematic-isotropic transitions were observed at 89 degre es C and 120 degrees C, respectively.