ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Side-chain functionalized polysiloxanes were prepared via polymer-analogous esterification of poly[(3-chloroformylpropyl)methylsiloxane] with 4-(4-hydroxyphenylazo)nitrobenzene (P1), 4-[4-(ω-hydroxyalkyloxy)phenylazo]nitrobenzene (P2-P4), 4-{4-[N-(2-hydroxyethyl)-N-methyl]anilinoazo}nitrobenzene (P5), 4-(4-hydroxypiperidino)nitrobenzene (P6), or 4-[4-(2-hydroxyethyl)piperidino]nitrobenzene (P7)., P1, P3, P4 and P5 exhibit liquid crystallinity, as deduced from differential scanning calorimetry, polarized microscopic observations and X-ray diffraction measurements. The liquid-crystalline phase of P1 and P5 is a nematic phase, and that of P3 and P4 is a smectic one. The second harmonic generation (SHG) measurement of a spin-coated film of P1 was carried out by the Maker fringe method using a Q-switched Nd:YAG laser (1064 nm). The SHG profile after the heat treatment of a spin-coated film suggests a perpendicular orientation of the mesogenic molecules to the glass substrate. The SH light intensity of a corona-poled film was 20-fold higher than that of a film which was only heated, though no differences were observed in their UV-vis absorption spectra. These findings suggest that the mesogenic-molecular dipole moments are aligned to the same direction in the crystalline or liquid-crystalline phase by a poling treatment.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1995.021960713
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