A team of researchers has challenged a fundamental principle of physics by observing particles of the same charge attracting each other under certain conditions, a phenomenon that appears to defy the law stated by French physicist Charles-Augustin de Coulomb in the 18th century.
Traditionally, it is believed that opposite charges attract while like charges repel. However, work published on March 1st in the journal
Nature Nanotechnology has shown that in water or certain alcohols, particles of the same charge can be attracted to one another. This discovery was made by placing tiny, charged silica microparticles in water or two types of alcohol and observing their behavior.
In water, positively charged particles repelled each other, in accordance with Coulomb's law. However, negatively charged particles formed tiny hexagonal structures within a specific pH range, akin to the acidity of coffee or milk. This behavior was reversed in alcohols like ethanol and isopropanol, where positive charges were attracted to each other.
To explain this phenomenon, the researchers proposed a model that takes into account the molecular nature of water, considering it not as a continuous medium, but composed of small electromagnetic dipoles. An "electrosolvation force" would emerge from the interaction between the water's negative oxygen and the negative silica particles, influenced by a global charge change after a proton transfer to the silica particles within a specific pH range.
This new model could have significant implications for understanding biomolecular condensates, which are essential in the study of human diseases. The researchers hope that this discovery will shed light on the fundamental mechanisms of diseases, highlighting the importance of their work in the field of biophysics.