1818-99-1Relevant academic research and scientific papers
Mesomorphic properties of diesters with p-substituted-arylazomethine pendant groups
Hernandez, Sandra A.,Garay, Raul O.
, p. 21 - 32 (2006)
The substituent steric and electronic effects on mesophase stability and glass-forming properties of a series of 1,4-bis-(4- n -alkyloxybenzoyloxy)-2- N -( p -Y-aryl)azomethinebenzenes were evaluated. The diesters showed a typical though mild dependence of the monotropic nematic-isotropic transition temperatures on the substituent size that was attributed to the conformational flexibility of the pendant azomethine group. In contrast, the dependence of the entropy change associated with the nematic-isotropic transition showed an atypical behavior ascribed to the extreme reduction of the mesogen axial ratio. The introduction of the bulky arylazomethine group on a lateral position originated significant crystallization supercooling. The appearance of glassy mesophases was detected in some of the diesters; the OEt and CF 3 groups were the more effective substituents to promote the formation of nematic glasses.
LIQUID CRYSTALS - 7. SMECTIC-NEMATIC TRANSITION TEMPERATURE AS A FUNCTION OF ALKYL END GROUP LENGTH IN p-PHENYLENE Di-p-n-ALKOXYBENZOATES.
Schroeder
, p. 229 - 240 (2007/10/02)
The Sm-N transition temperatures of the C//1-C//1//2 homologs of some p-phenylene di-p-n-alkoxybenzoates were studied. For three homologous series of these esters (unsubstituted, methyl-substituted, and chlorosubstituted on the central phenylene ring), th
