Free volumes studies in Thymoquinone and Carvone β-cyclodextrin nanoparticles by positron annihilation lifetime spectroscopy

16th International Conference on Positron Annihilation

Marques, M. F. Ferreira^1,2 ; Gordo, P.M.^2 ; Da Silva, A. Moreira^3

Department of Chemical and Biological Engineering, ISEC-IPC, R. Pedro Nunes, Quinta da Nora, 3030-199 Coimbra, Portugal^1

CEMUC, Department of Physics, Coimbra University, R. Larga, 3004-516 Coimbra, Portugal^2

Department of Food Science and Technology, ESAC-IPC, Bencanta, 3040-316 Coimbra, Portugal^3

关键词: Beta-cyclodextrin;    Carvone;    Cyclodextrin inclusion compound;    Long lifetime;    o-Ps lifetime;    Positron annihilation lifetime spectroscopy;    Ps formations;    Thymoquinone;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/443/1/012053/pdf
DOI  :  10.1088/1742-6596/443/1/012053

来源: IOP

【 摘 要 】

Positron annihilation lifetime spectroscopy is used to study free volume in β-cyclodextrin with the encapsulation of thymoquinone and S-carvone, in samples covering the guest to host fraction range from 1:0.1 to 1:1. The results clearly indicate the presence of long lifetime components related to Ps-formation. Although the behavior of the two guests is different, in both cases the results indicate the formation of 1:1 cyclodextrin inclusion compounds. Data show that the addition of carvone to β-cyclodextrin results in a decrease of the o-Ps lifetime corresponding to a reduction of the average radius of cavities from 2.41 A to 2.29 A, whereas the addition of thymoquine decreases the radius from 2.57 A to 2.35 A. In turn, the intensity varied from 20.55 to 19.20% and from 20.83 to 0.41%, respectively.