Scientists Create and Manipulate Nanoscale
"Water Wires"

As pressure was continually applied, it nudged the oxygen atoms in adjacent
water molecules closer together than oxygen atoms in bulk water. This suggests
that the wires may be good proton conductors, since protons travel in water by
“hopping” from one molecule to the next, choosing the path of least water-to-water
distance.

“Understanding proton transport at the nanoscale in water wires could be useful in the development of applications such as hydrogen fuel cell technology.”
— Thomas Vogt

Next, Vogt and his group heated the sample to 200 degrees Celsius. Under pressure and heat, the natrolite structure expanded non-uniformly — more in one direction than the other. As a result, some water molecules moved closer together while others moved farther apart. This shifted the direction of the shortest water-to-water distance, creating a new preferred hopping route for protons. Because the direction of proton hopping is what defines the water wires, this shift also changed the wires’ orientation.

Understanding proton transport at the nanoscale in water wires could be useful
in the development of applications such as hydrogen fuel cell technology, which
also involves proton transport. It may also help scientists better understand biological processes that depend on proton transport, such as the production of
adenosine triphosphate, the compound that provides the energy for many
cellular functions. The scientists followed the natrolite’s structural changes at
National Synchrotron Light Source (NSLS) beamline X7A.

This research was funded by a grant from Brookhaven’s Laboratory Directed
Research and Development (LDRD) program. Brookhaven’s Yongjae Lee, C. Dave
Martin and John B. Parise from Stony Brook University and Joe Hriljac of the
University of Birmingham, United Kingdom, also participated in the research.

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