The behavior of water in the ultra-confinement of natural minerals - A 1D structural glass


  Paul Ben Ishai  
Department of Physics, Ariel University

What would happen if the H-bond was removed from water, even though water was not in a gaseous state? Certainly, its delinquent anomalous behavior would be absent, but so would be the collective phenomena that make it so unique. This situation can be approached when water molecules are ultra-confined in sub-nanometer sized channels, present in natural minerals, such as cordierite. These channels are an integral part of the crystal lattice. The diameter is often of the same order of magnitude as the diameter of a water molecule, 4-5 Å. Under such conditions water entrapped in them at the time of formation, but not chemically bound, can no longer behave as “water”. But rather than conform, these extreme conditions lead to unusual behaviours. Concepts like H-bonding and clustering are now not relevant and a new class of dynamics must arise for these molecules. These crystals are, per force, highly anisotropic, leading to very different dielectric properties depending of the crystal axis chosen. DC conductivity is sometimes present, but not necessarily along the water channels. Surprisingly, despite the absence of H-bonds water still exhibits cooperative features in its dielectric response, such a glass transition, albeit in 1 dimension only. This, and other phenomena will form the basis of this presentation.