Ice crystallization observed in highly supercooled confined water

Abstract : We investigate the state of water confined in the cylindrical pores of MCM-41 type mesoporous silica, with pore diameters of 2.8 nm and 4.5 nm, over the temperature range 160-290 K by combining small angle neutron scattering and wide angle diffraction. This allows us to observe simultaneously the intermolecular correlations in the local water structure (which shows up in a main water peak around Q = 1.7 Å −1), the two-dimensional hexagonal arrangement of water cylinders in the silica matrix (which gives rise to a pronounced Bragg peak around Q = 0.2 Å −1), and the so-called Porod scattering at smaller Q, which arises from larger scale interfacial scattering within the material. In the literature, the temperature evolution of the intensity of this Bragg peak has been interpreted as the signature of a density minimum in confined water at approximately 210 K. Here we show that, under the conditions of our experiment, a fraction of freezable water coexists with a layer of non-freezable water within the pore volume. The temperature dependence of all three aspects of our data, as well as comparing the data from two different pore sizes, leads us to conclude that the observed variation in the intensity of the main Bragg diffraction peak is actually caused by a liquid to ice transition in the freezable fraction of confined water.
Complete list of metadatas

Cited literature [54 references]  Display  Hide  Download

https://hal.sorbonne-universite.fr/hal-02342170
Contributor : Gestionnaire Hal-Su <>
Submitted on : Friday, November 8, 2019 - 12:56:30 PM
Last modification on : Saturday, November 9, 2019 - 2:08:47 AM

File

PCCP_Ice-2_GL.pdf
Files produced by the author(s)

Identifiers

Citation

E. Stefanutti, L. Bove, G. Lelong, M. Ricci, A. Soper, et al.. Ice crystallization observed in highly supercooled confined water. Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2019, 21 (9), pp.4931-4938. ⟨10.1039/C8CP07585A⟩. ⟨hal-02342170⟩

Share

Metrics

Record views

31

Files downloads

8