Bulk and Interfacial Glass Transitions of Water

Abstract

Fast scanning calorimetry (FSC) was employed to investigate glass softening dynamics in bulk-like and ultrathin glassy water films. Bulk-like water samples were prepared by vapor-deposition on the surface of a tungsten filament near 140 K where vapor-deposition results in low enthalpy glassy water films. The vapor-deposition approach was also used to grow multiple nanoscale (approximately 50 nm thick) water films alternated with benzene and methanoic films of similar dimensions. When heated from cryogenic temperatures, the ultrathin water films underwent a well manifested glass softening transition at temperatures 20 K below the onset of crystallization. However, no such transition was observed in bulk-like samples prior to their crystallization. These results indicate that thin-film water demonstrates glass softening dynamics that are dramatically distinct from those of the bulk phase. We attribute these differences to water's interfacial glass transition, which occurs at temperatures tens of degrees lower than that in the bulk. Implications of these findings for past studies of glass softening dynamics in various glassy water samples are discussed.

The role of thermodynamic stability in the characteristics of the devitrification front of vapour-deposited glasses of toluene

“…Still, our technique cannot distinguish between the existence of one or two fronts, coming from the surface and the interface with the substrate, and thus, our growth rate values can differ up to a factor 2 when compared with those obtained by other techniques which can distinguish the evolution of single fronts. 13 Our front velocities are comparable to previous fast scanning calorimetry measurements from Bhattacharya et al 43 on toluene thin films.…”

“…In a previous study, Bhattacharya et al found that stable toluene glasses transformed via a front mechanism up to thicknesses of around 2 mm. 43 With our technique, we are limited in film thickness, so it is not possible for us to determine the cross-over length maximum for stable glasses. Even though we do not see variations in the growth front velocity between glasses grown at different deposition temperatures but encoded with the same limiting fictive temperature, we do observe remarkable changes in their cross-over lengths.…”

1. Influence of Thermal Prehistory on Crystal Nucleation and Growth in Polymers

“…500 Ks −1 , was developed by Hager [57] and, even for rates up to 10 7 Ks −1 , by Allen and co-workers [30,58,59]. Similar approaches were used to study the behavior of metastable materials like vapor deposited films [60][61][62][63][64][65]. But, on the other hand, the investigation of metastable phase formation is possible only if the same high-controlled cooling rates are available too.…”

Fast scanning calorimetry studies of the glass transition in doped amorphous solid water: Evidence for the existence of a unique vicinal phase

“…18 Recent single molecular spectroscopy experiments with Rhodamine 700 in hyperquenched glassy water, conducted by Jankowiak and coworkers, 19 indicate that water is not a viscous liquid at temperatures above 140 K, and thus, are in stark contrast to the conclusions of the ESR study. 10 Finally, Bhattacharya et al demonstrated that nanoscale films of amorphous solid water (ASW) show a weak glass transition prior to crystallization, while the bulk-like pure ASW samples do not, 20 which puts in question findings of Souda's group. 6,8,9,21 While recent experimental evidence provides strong support to the notion that water does not undergo a glass transition prior to crystallization, the experimental results which are in contrast with such a view cannot simply be discarded or ignored.…”