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Hydrogen-bonded liquid-crystalline polyurethane complexes with 4-dodecyloxybenzoic acid

We prepared novel hydrogen-bonded liquid-crystalline polyurethane complexes from 4-dodecyloxybenzoic acid and polyurethane containing pyridyl units in the main chain, based on 2, 6-bis(hydroxymethyl) pyridine. The complexes were investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffractometry. The liquid-crystalline polyurethane complexes were formed at acid/pyridine molar ratios up to 0.4 exhibiting crystal-smectic and smectic-nematic transitions similar to those of the polyurethane complexes with pendant pyridyl units reported on recently. The analogous low-molar mass urethane complex exhibited lower isotropization temperature and a less ordered smectic phase than the polymeric complexes.

supramolecular polyurethanes ; hydrogen bonding ; 4-dodecyloxybenzoic acid ; liquid-crystalline polymers (LCP)

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