ISSN:
0887-624X
Keywords:
azobenzene
;
polyacrylates
;
liquid crystals
;
photoresponsive polymers
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The synthesis and characterization are reported of two new series of structurally isomeric polyacrylates containing the azobenzene moiety spaced away from the backbone by a hexamethylene spacer and substituted in 4-position with linear alkoxy groups (C1—C6, C10) and with a lateral methyl group in 2′- or 3′-position. Thermal optical and X-ray analyses of the prepared polymer samples, with molecular weight ranging from 50 × 103 to 35 × 104 Dalton (M̄w/M̄n = 2-3), provide evidences for the establishment of liquid crystalline behavior in the melt in a fairly broad range of temperature. In any case, quenching from the mesophase allows for the lock-in of the liquid crystalline structure in the glassy state. The presence of the lateral methyl-substitutents causes a drop as high as 50-100 K. in the stability of the mesophase with respect to the corresponding samples of the methyl-unsubstituted series. A parallel depletion of the smectogenic character is also observed. Typical even-odd effects on the isotropization temperature and relevant thermodynamic parameters have been detected along with the formation of interdigitated smectic structures.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1991.080291304
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