Scientists at EPFL have been able to observe single protons moving at the interface between water and a solid surface. Their research reveals the strong interactions of these charges with surfaces.
The H+ proton consists of a single ion of hydrogen, the smallest and lightest of all the chemical elements. These protons occur naturally in water where a tiny proportion of molecules separate spontaneously. Their amount in a liquid determines whether the solution is acidic or basic. Protons are also extremely mobile, moving through water by jumping from one water molecule to another.
Proton transport at water-solid interfaces
The way this transport process works in a body of water is relatively well understood. But the presence of a solid surface can dramatically affect how protons behave, and scientists currently have very little in the way of tools to measure these movements at water-solid interfaces. In this new study, Jean Comtet, a postdoctoral researcher at EPFL’s School of Engineering (STI), has provided the first-ever glimpse of the behavior of protons when water comes into contact with a solid surface, going down to the ultimate scale of single proton and single charge. His findings, published in the journal Nature Nanotechnology, reveal that protons tend to move along the interface between these two mediums. The study benefited from the help of researchers from the Department of Chemistry at the École Normale Supérieure (ENS) in Paris who carried out simulations.
Source: “Watching single protons moving at water-solid interfaces”, Valerie Geneux, EPFL News