Polymer−Cyclodextrin Inclusion Compounds:  Toward New Aspects of Their Inclusion Mechanism

Abstract

α-Cyclodextrin inclusion compounds were prepared in the presence of a polymer and a small molecule model for the polymer repeat unit. By means of this technique, we are able to demonstrate that α-cyclodextrin prefers the inclusion of the longer molecular chain guest. Comparison of the cyclodextrin inclusion compounds formed with poly(ε-caprolactone) and hexanoic acid, separately and from solution containing both poly(ε-caprolactone) and hexanoic acid in varying amounts, enables us to draw certain conclusions concerning both the thermodynamic and kinetic aspects of poly(ε-caprolactone)−α-cyclodextrin inclusion compound formation. Differential scanning calorimetry, Fourier transform infrared, and wide-angle X-ray diffraction have been used to verify the formation and successfully characterize all inclusion compounds.