Neutron diffraction studies of structural phase transformations for water–ice in confined geometry

Neutron diffraction measurements have been made for D2O water in the confined geometry of various mesoporous silicas over a wide temperature range. The data have been taken for cooling and heating runs incorporating the nucleation and melting of the crystalline phases and the super-cooled liquid phase. The crystalline forms and the temperatures at which they change are shown to be strongly dependent on the pore size and type of silica used as the confining medium and relate to the phase relationship between hexagonal ice [Ih] and cubic ice [Ic].