Polymer-cyclodextrin inclusion compounds: Toward new aspects of their inclusion mechanism

alpha -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 alpha -cyclodextrin prefers the inclusion of the longer molecular chain guest. Comparison of the cyclodextrin inclusion compounds formed with poly(epsilon -caprolactone) and hexanoic acid, separately and from solution containing both poly(epsilon -caprolactone) and hexanoic acid in varying amounts, enables us to draw certain conclusions concerning both the thermodynamic and kinetic aspects of poly(epsilon -caprolactone)-alpha -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.