Positron annihilation and speed of sound in the systems containing beta cyclodextrin

Positron annihilation measurements were performed in aqueous solutions of beta-cyclodextrin, as well as in solid mixtures of this sugar with a long-chained alcohol, n-nonanol. Additionally, acoustic (sound speed, density and compressibility) experiments were done in aqueous beta-cyclodextrin and tert-butanol systems and in a three-component water-beta-cyclodextrin-tert-butanol system. The results show that in aqueous solution cyclodextrin does not form inclusive complexes with alcohol, while solid sugar-alcohol mixtures undergo slow changes in time, most probably caused by exchange of guest between interior and exterior of the host molecule. (authors)