Water conducts electricity, that’s a fact. But this process, one of the most fundamental in chemistry and biology, has puzzled scientists for decades. A recent study nevertheless tends to shed light on this process considered to be one of the most mysterious relay races in nature.
Telling us that water is a great conductor of electricity is not surprising in itself, it is also a fact taught since primary school. But this fundamental process in chemistry and biology has eluded firm and definitive explanation for decades. A recent study by researchers at Yale University in the United States, however, gives us an overall picture of the process.
The study, led by Mark Johnson, involved observing water molecules passing along protons — positively charged subatomic particles — using spectroscopy, a process that allows researchers to shoot light at molecules and see what’s going on inside. The goal is to understand How? ‘Or’ What molecules raced past charged particles in complex arrangements. Until now, researchers were familiar with this process described by the chemist Theodor Grotthuss in 1806, who incidentally gave his name to this mechanism. But the details of this process have always remained somewhat murky.
The mechanism is that an excess of protons — the positively charged subatomic particles within atoms — are transmitted through the hydrogen bonds of water molecules or other hydrogen-bonded liquids. By this mechanism, a water molecule can « pick up » an excess charge and pass it on to a neighbor almost instantaneously. These exchanges are fundamental to understanding the behavior of water in biological and industrial parameters. But they are also so fast and the vibrations between molecules so large that the process cannot be captured using traditional spectroscopy.
The researchers then had the idea of freezing the process, thus allowing them to visualize the Grotthuss mechanism thanks to a kind of “spectroscopic snapshots”. « We have discovered a kind of Rosetta Stone that reveals color-coded structural information said Mark Johnson. ‘We were able to reveal a sequence of concerted deformations like the frames of a movie”. This new study will allow researchers to better understand the conductivity of water at the molecular level, a phenomenon that keeps us alive and crucial in many chemical reactions on Earth.
The study will also allow a better understanding of the chemical processes that occur at the surface of the water. There is a debate among scientists today as to whether surface water is more or less acidic than most water. This new imaging technique could answer that question once and for all.