Scientists from Germany, Russia and Czech Republic have succeeded to pack water molecules in a gem stone in such a way that signs of ferroelectric order were observed for the first time in ice or an aqueous system. This is an important contribution to the understanding of the physics of water and opens the door to better understand the functioning of proteins and cells. The journal Nature Communications reported on it in its latest issue.
Water is not nearly as clear as it seems. Although water in daily life is pervasive as ice,
liquid and vapor, and even though it is scientifically studied so intensely in every detail like no
other material on earth, its physics is by far not understood yet. Why water is boiling, for
example, only at 100 degrees centigrade, can be explained only by means of quantum mechanics: The
reason is the strong electric fields by the two hydrogen atoms on oxygen in H
2O.
Even in crystalline ice the electric dipoles do not order. This implies that, that contrary
to all simple models, ice is not ferroelectric. And this is true not only for ordinary ice which is
referred to as hexagonal ice I
h, but also for 15 other forms, which are observed only under extreme conditions in the
laboratory or on the planets and moons of our solar system. Bridges formed by hydrogen bonds
between adjacent water molecules prevent this order.
A group of scientists from Universität Stuttgart, from the Moscow Institute of Physics and
Technology, the Academy of Sciences in Prague and other German, Russian and Czech research
institutions have now succeeded, to pack water molecules in a gem in such way that they could for
the first time observe signs of ferroelectric. For this purpose they use beryl crystals: a family
of naturally occurring minerals, of which the emerald is the most famous with its fascinating green
color.
Isolated but still interacting
In the nanotubes of crystals individual water molecules are incorporated, which are isolated
from each other far enough so they cannot form hydrogen bonds, but close enough to electrically
feel themselves. Using optical investigations in a wide spectral range from infrared, via THz
frequencies to radio waves, the H
2O molecules could be observed directly. It was recognized that the electric dipoles are
all aligned when the temperature is lowered to near absolute zero of -273 degrees Celsius. Only
quantum fluctuations prevent the perfect ferroelectric order of the water molecules.
Impact on biology and data storage
The physicists suspect that the ferroelectricity of these isolated water molecules plays an
important role in biological systems. "Maybe we can now better understand the functioning of
proteins and cells, the electrical impulse transmission by means of the protons in nerve" hopes
Prof. Martin Dressel from Physics 1 of University of Stuttgart. Perhaps one could these ideas now
apply to fuel cells and data memories, in light sources and other electronic devices on the
nanometer scale.
*Original publication:
Boris Gorshunov et al., Martin Dressel: Incipient ferroelectricity of water molecules
confined to nano-channels of beryl, Nature Communications 7, 12842 (2016)
http://www.nature.com/ncomms/2016/160930/ncomms12842/full/ncomms12842.html
Contact:
Prof. Dr. Martin Dressel, Universität Stuttgart, 1. Physikalisches Institut Tel.: 0711-685
64946, Email: dressel@pi1.physik.uni-stuttgart.de
