Design and Synthesis of a New Family of Amphiphilic beta-Cyclodextrin Liquid Crystals.

Abstract

The field of liquid crystals has fascinated scientists since 1888 when a molecule of cholesteryl benzoate exhibited two different melting points. It corresponds to a state of matter between the isotropic liquid and the crystalline solid-state. Since then, the field has grown, and liquid crystal-based materials have become an important component of our lives. Cyclodextrin (CD) are polyhydroxylated macrocycles containing 6-8 units of beta-D-glucopyranose units linked together via a series of alpha-1,4-glycosidic linkages. The formed macrocycles are shaped like a truncated cone that combines two hydrophilic surfaces and a hydrophobic cavity that can be used to form inclusion complexes with different organic molecules. Our group has been developing chemistries to modify the two hydrophilic surfaces of CDs by a variety of chemical methodologies to generate amphiphilic molecules capable of self-assembling into liquid crystalline mesophases. This thesis focuses on the synthesis a new family of amphiphilic CDs for liquid crystal research. These CD-derivatives can be easily obtained via polyesterification at one of the hydrophilic faces with hydrophobic aliphatic chains and installation of functionalized oligoethylene glycols at the other surface via the copper(I)-catalyzed Huigsen 1,3-dipolar cycloaddition. These novel amphiphilic CD derivatives have been characterized by polarized optical microscopy, thermogravimetric analysis and differential scanning calorimetry.