A Comparative Study on the Formation and Spectral Properties of the Polypseudorotaxanes of β-Cyclodextrin and Poly(propylene glycol) under Different Conditions

The results of this paper answer the questions, “Can hydrothermal conditions with higher pressure and higher temperature be used for the preparation of polypseudorotaxanes of cyclodextrins with polymers? If yes, do the prepared polypseudorotaxanes have different stoichiometries and spectral properties from those obtained by the same hosts and guests under nonhydrothermal conditions?” Two polypseudorotaxanes, 1 and 2, formed by PPG and β-CD, were prepared with magnetic stirring and a hydrothermal method, respectively, in this work. Our results indicate that different host–guest stoichiometries and stacking forms between 1 and 2 significantly change their structural properties and thermal behaviors, implying that a close relationship exists between preparation conditions and spectral properties of the polypseudorotaxanes.