| Abstract: | Cellulose acetate (DS = 2.45) was extensively investigated by Circular Dichroism (CD) in acetonitrile and dioxane. We found great differences between the CD spectra of a 1 wt % acetonitrile solution and the corresponding dioxane solution of cellulose acetate (CA) indicating that the macromolecules exist in those solutions in different molecular arrangements (e.g., persistence length, solvatation shell). The resulting morphologies could be transformed reversibly into each other, as we found by measuring the CA in mixtures of both solvents. Solid CA films show discernible CD spectra depending on the solvent they were evaporated from. In this way, we prepared solid films of the same polysaccharide owning different chiral properties. Furthermore, changes in the spectra occurred with increasing CA concentration. Basing upon our findings, some general statements concerning the polymer behavior of CA are possible. © 1999 John Wiley & Sons, Inc. Biopoly 50: 163–166, 1999 |
