title: Mid-infrared spectroscopic investigation of the perfect vitrification of poly(ethylene glycol) aqueous solutions.
abstract: Crystallization/recrystallization behaviors of poly(ethylene glycol) (PEG) aqueous solutions with water contents (WC's) of ∼36-51 wt % were investigated by temperature-variable mid-infrared spectroscopy. At a WC of 43.2 wt %, crystallization and recrystallization of water and PEG were not observed. At this specific WC value (WCPV), perfect vitrification occurred. Below and above the WCPV value, crystallization/recrystallization behaviors changed drastically. The crystallization temperature below WCPV (237 K) was ∼10 K greater than that above WCPV (226 K). Recrystallization above and below WCPV occurred in one (213 K) and two (198 and 210 K) steps, respectively. These findings resulted from the difference in the (re)crystallization behaviors of water molecules associated with PEG chains with helical and random-coil conformations. These two types of water molecules might have limiting concentrations for their (re)crystallization, indicating that perfect vitrification might have occurred when the concentrations of the two types of water molecules were less than the limiting concentrations of their (re)crystallization.
authors.affiliation: Department of Environmental Applied Chemistry, Graduate School of Science and Engineering, University of Toyama , 3190 Gofuku, Toyama 930-8555, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Gemmei-Ide
authors.affiliation: Department of Environmental Applied Chemistry, Graduate School of Science and Engineering, University of Toyama , 3190 Gofuku, Toyama 930-8555, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyashita
authors.affiliation: Department of Environmental Applied Chemistry, Graduate School of Science and Engineering, University of Toyama , 3190 Gofuku, Toyama 930-8555, Japan.
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kagaya
authors.affiliation: Department of Environmental Applied Chemistry, Graduate School of Science and Engineering, University of Toyama , 3190 Gofuku, Toyama 930-8555, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kitano