Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5186034 | Polymer | 2009 | 6 Pages |
A new series of thermotropic ionic polyurethane-urea (PUU) liquid crystals (LCs) were synthesized, each by using the corresponding diisocyanate, 4,4â²-bis(6-hydroxyhexoxy)biphenyl, and sodium 2,5-diaminobenzenesulfonate. Morphology, phase transition temperatures, and spectroscopic characteristics of the PUU LCs are reported. Each PUU exhibits a monotropic liquid crystal phase upon slow cooling. The PUU LC phase texture is visible by polarized optical microscopy (POM) and is dependent upon the PUU isocyanate precursor; 1,6-diisocyanatohexane (HDI) and 5-isocyanato-1-(isocyanatomethyl)-1,3,3,-trimethylcyclohexane (IPDI) polymers have schlieren textures, whereas 2,4-diisocyanato-1-methylbenzene (TDI) and methylenebis(4-phenylisocyanate) (MDI) polymers show grain textures.
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