Lyotropic liquid‐crystalline behavior of polyisocyanodipeptides |
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| Authors: | Gerald A Metselaar Sander J Wezenberg Jeroen J L M Cornelissen Roeland J M Nolte Alan E Rowan |
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| Institution: | 1. Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands;2. Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The NetherlandsInstitute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands |
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| Abstract: | Rigid, helical polyisocyanodipeptides derived from alanine (PIAAs) that form lyotropic liquid‐crystalline (LC) phases in tetrachloroethane are presented. An investigation by optical microscopy between crossed polarizers demonstrated that PIAAs prepared by the polymerization of isocyanodipeptide monomers with an activated tetrakis isocyanide nickel(II) catalyst could form cholesteric LC phases in tetrachloroethane in concentrations between 18 and 30 wt %. Cholesteric LC phases that were formed in solutions of greater than 25 wt % displayed a reversal of the cholesteric helix upon annealing at 50 °C. Diastereomeric PIAA mixtures displayed cholesteric LC behavior only when the PIAAs had the same helix screw sense. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 981–988, 2007 |
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| Keywords: | chiral helical polymers helical structures liquid‐crystalline polymers (LCP) liquid crystals polyisocyanides |
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