Molecular Conformation and Intermolecular Interactions of Linear and Cyclic Amylose Derivatives in Solution

Abstract

Four kinds of rigid and semiflexible ring polymers are synthesized from flexible cyclic amylose. Their conformational properties in dilute solution are determined from dimensional and hydrodynamic properties in terms of the wormlike ring model. The helix rise per residue h of some ring polymers is larger or smaller than that for the corresponding linear chains, indicating that the local helical structure of the ring polymer is not the same as that for the linear chain. Intermolecular interactions detected by the second virial coefficient and chiral recognition ability of some ring polymers are different from the linear chain, suggesting the local structural change causes the intermolecular interactions. The study also finds that rigid ring polymers can form liquid crystal phase at high concentration. X-ray diffraction results suggest that the ring chains form pseudo rodlike conformation in the liquid crystal phase, showing that intermolecular excluded volume effects significantly influence the conformation of the polymer chains.

Solution characterization of a hyperbranched polysaccharide carbamate derivative and specific phase separation behavior due to chain branching

“…[15][16][17] On the contrary, we found that cyclic amylose tris(phenylcarbamate) (cATPC) has a negative second virial coefficient in the theta solvent of linear amylose tris(phenylcarbamate) (ATPC), 18 indicating that the intermolecular interactions between the strained helices of the rigid cyclic cATPC chains via solvent molecules are different from those of the linear chain. 19 Highly branched cyclic dextrin (HBCD), which was developed by Takata et al, 20,21 is an amylopectin-based polysaccharide that has a relatively narrow molar mass distribution. We have recently prepared a 3,5-dimethylphenylcarbamate derivative of HBCD (HDMPC) 22 which was only soluble in good solvents.…”

“…15–17 On the contrary, we found that cyclic amylose tris(phenylcarbamate) (cATPC) has a negative second virial coefficient in the theta solvent of linear amylose tris(phenylcarbamate) (ATPC), 18 indicating that the intermolecular interactions between the strained helices of the rigid cyclic cATPC chains via solvent molecules are different from those of the linear chain. 19…”