title: Radical re-appraisal of water structure in hydrophilic confinement.
abstract: The structure of water confined in MCM41 silica cylindrical pores is studied to determine whether confined water is simply a version of the bulk liquid which can be substantially supercooled without crystallisation. A combination of total neutron scattering from the porous silica, both wet and dry, and computer simulation using a realistic model of the scattering substrate is used. The water in the pore is divided into three regions: core, interfacial and overlap. The average local densities of water in these simulations are found to be about 20% lower than bulk water density, while the density in the core region is below, but closer to, the bulk density. There is a decrease in both local and core densities when the temperature is lowered from 298 K to 210 K. The radical proposal is made here that water in hydrophilic confinement is under significant tension, around -100 MPa, inside the pore.
authors.affiliation: ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK.
authors.forename: Alan K
authors.initials: AK
authors.lastname: Soper
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