Shape Dependence in the Formation of Condensed Phases Exhibited by Disubstituted Sucrose Esters

• Published in: Chemistry : a European journal 2007-01, Vol.13 (6), p.1763-1775
• Main Authors: Molinier, Valérie, Kouwer, Paul J. J., Fitremann, Juliette, Bouchu, Alain, Mackenzie, Grahame, Queneau, Yves, Goodby, John W.
• Format: Article
• Language: English
• Subjects: Calorimetry, Differential Scanning; Chemical Sciences; Esters - chemistry; fatty acids; glycolipids; Glycolipids - chemistry; Isomerism; Lipid Bilayers - chemistry; liquid crystals; Microscopy, Polarization; Organic chemistry; Phase Transition; phase transitions; Stearates - chemistry; Sucrose - chemistry; sucrose esters; Temperature; X-Ray Diffraction
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200600368

We report on the self‐organizing properties of sucrose esters that are di‐(1′,6′, 1′,6, and 6,6′)‐substituted with aliphatic chains of identical or different chain lengths and levels of saturation. For the materials possessing two saturated aliphatic chains, the compounds exhibited thermotropic lamellar smectic A phases. A remarkable new phase transition was observed for the di‐octadecanoyl homologue in which one smectic A phase transformed into another with a continuous change in layer spacing, but with a discontinuous change in the correlation length. The incorporation of long cis‐unsaturated chains led to increased cross‐sectional areas of the chains relative to the sucrose head groups and, hence, columnar phases were observed. Smooth transition: The self‐organizing properties of a variety of disubstituted sucrose esters are reported (see structure). Materials with two saturated aliphatic chains exhibited thermotropic, lamellar smectic A phases. A remarkable new phase transition was observed for the di‐octadecanoyl homologue, in which one smectic A phase (see polarizing light microscopy image) transformed into another with a continuous change in layer spacing, but a discontinuous change in correlation length.