title: Neutron diffraction of ice in hydrogels.
abstract: Neutron diffraction patterns for deuterated poly-N,N,-dimethylacrylamide (PDMAA) hydrogels were measured from 10 to 300 K to investigate the structure and properties of water in the gels. Diffraction peaks observed below 250 K indicate the existence of ice in the hydrogels. Some diffraction peaks from the ice are at lower diffraction angles than those in ordinary hexagonal ice (Ih). These shifts in peaks indicate that the lattice constants of the a and c axes in the ice are about 0.29 and 0.3% higher than those in ice Ih, respectively. The results show that bulk low-density ice can exist in PDMAA hydrogels. The distortions in the lattice structure of ice imply significant interactions between water molecules and the surrounding polymer chains, which play an important role in the chemical and mechanical properties of the hydrogel.
authors.affiliation: Quantum Beam Science Center, Japan Atomic Energy Agency , 2-4 Shirakata-Shirane, Naka-gun, Tokai 319-1195, Japan.
authors.forename: Yurina
authors.initials: Y
authors.lastname: Sekine
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ikeda-Fukazawa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Aizawa
authors.forename: Riki
authors.initials: R
authors.lastname: Kobayashi
authors.forename: Songxue
authors.initials: S
authors.lastname: Chi
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Fernandez-Baca
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukazawa