"The ideal gas contribution to surface tension"


Contrarily to what is often believed, the kinetic part of the stress tensor can contribute to the surface tension of a liquid.

Surface tension, the tendency of fluid interfaces to behave elastically and minimize their surface, develops in the first two-to-three molecular layers at the surface of the liquid. In this region, the ordering of water molecules gives rise to a surprising effect: the rotation of strongly oriented molecules adds an important contribution to the surface tension of the liquid, which can account up to 15% of the total, as computer simulations of Marcello Sega and colleagues show.

Marcello Sega, Balázs Fábián, and Pál Jedlovszky, "Nonzero Ideal Gas Contribution to the Surface Tension of Water", J. Phys. Chem. Lett. 8, 2608-2612 (2017). DOI: 10.1021/acs.jpclett.7b01024