15:15 〜 15:30
▼ [16p-Z13-7] Characterization of Hydration State of Polyethylene Glycol based on Broadband Dielectric Spectroscopy.
キーワード：Hydration, Polyethylene glycol, Contact lens
The aim of this study is to elaborate the application prefer of PEG with various Mw in the CLs package solution from the aspect of hydration state. Therefore, a broadband dielectric spectroscopy covering the microwave-terahertz (THz)-far infrared (FIR) range (Fig. 1), 0.1 GHz to 18 THz, was performed, to characterize PEG solutions with different molecular weights (Mw) at room temperature. The moisturizing effect of PEG can be described by the number of water molecules restricted by PEG molecules and the degree of the caused dynamical slowing down of water molecules. Fig. 2 shows that with the increasing Mw, the ratio of hydration water decreases, which proves that longer chains make it harder to ensure each monomer to interact with the maximum number of water molecules. The PEG with larger Mw can restrict water molecules tighter with the retardation factor from 2.09 to 2.25. The effect of Mw on the structural disorder of hydrogen bond networks is not significant, which should be attributed to the offset between the increase of local forces in the hydration layer and the decrease of hydration water proportion. The obtained characterization of the hydration effect of PEG in the dependence of Mw quantitatively describes better moisturizing effect of CLs package solution with lower-Mw PEG, but also is beneficial to other biological and medical preservation techniques.