The structure of water: Entropy determines whether ions stick

Key Points:

• Researchers from TU Wien, University of Vienna, and University of Oslo have demonstrated that water molecules form short-lived, statistically ordered structures around ions on nanosecond timescales, affecting how charged particles adhere to surfaces.
• The study reveals that ions carry a dynamic "dance" of water molecules with them, where smaller ions like lithium create more ordered water shells, leading to lower entropy states that make direct surface attachment less likely.
• By combining atomic force microscopy, molecular simulations, and spectroscopy, the team developed a thermodynamic model that quantitatively describes ion adsorption, incorporating electrostatic attraction, entropy, and water molecule interactions.
• This research provides new insights critical for understanding processes in batteries, fuel cells, catalysts, and biological membranes, emphasizing physical water-ion interactions rather than unsupported claims like the "memory of water."
• The findings, published in Science Advances, clarify that water's role is a dynamic physical phenomenon without any esoteric or information-storage properties.