Solvent-Responsive Behavior of Inclusion Complexes Between Amylose and Polytetrahydrofuran

Abstract

Highly crystalline amylose–polytetrahydrofuran (PTHF) complexes can be obtained by employing organic solvents as washing agents after complex formation. The X-ray diffraction (XRD) of the washed complexes appear sharp at 12.9°–13.2° and 19.6°–20.1°, clear signs of the presence of V6I-amylose. Other diffraction peaks correlate with V6II-amylose, which indicates that the complexed amylose helices are in the form of an intermediate or a mixture of V6I- and V6II-amylose. SEM imaging reveals that the amylose–PTHF complexes crystallize in the form of lamellae, which aggregate in a round shape on top of one another with a diameter around 4–8 µm. Some lamellas aggregate as flower-like or flat-surface spherulitic crystals. There is a visible matrix in between the aggregated lamellas which shows that a part of the amylose–PTHF complexes is amorphous