Netsu Sokutei, 42 (2), p. 69, (2015)



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

Amylose carbamate derivatives are suitable to investigate the relationship between the global conformation and local (intra- and/or intermolecular) interactions because it has completely regular stereochemical structure. In this paper, we summarized our recent research for the global conformation influenced by intramolecular hydrogen bonds, packing of side groups, and intermolecular hydrogen bonds between the polymer and solvent molecules. Furthermore, isothermal calorimetry measurements were carried out for an amylose derivative in optically active solvents in which dimensional properties significantly change with enantiomer excess. Cyclic amylose derivative molecules which behave as rigid (or semiflexible) rings in solution were also reported. In some cases, the same helical structure and chain stiffness were found both for linear and cyclic chains in solution and significant topological interactions were observed for cyclic polymers as positive second virial coefficients in a theta solvent. In other cases, we observed appreciably different helical structures between linear and cyclic polymers. Moreover, intermolecular interactions between two segments are crucially different between linear and cyclic polymers. This is a characteristic feature for rigid cyclic polymers in solution.