Synthesis of Hydrophobic Carbohydrate Polymers and Their Formation of Thermotropic Liquid Crystalline Phases

The first synthesis of enantiopure glucose octyl ether polyamido-saccharides (GOE-PAS) with a defined molecular weight and narrow dispersity is reported using a controlled anionic ring-opening polymerization of a glucose-derived beta-lactam sugar monomer possessing octyl ether chains. This new polymer structure is characterized by NMR, infrared (IR), optical rotation, gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). At room temperature, the polymers form lamellar (Lam) phases. Upon heating to mild temperatures (ca. 60 degrees C), the shortest polymer shows a direct transition to the isotropic (Iso) liquid state, while the longer polymers give rise to a hexagonal columnar (Col(h)) phase before becoming isotropic at higher temperatures (ca. 120 degrees C).