Pairwise association of neopentane as a function of hydrostatic pressure

•Pairwise hydrophobic interaction of neopentane depends upon pressure.•Pairwise hydrophobic interaction strength increases with hydrostatic pressure.•This strengthening is due to the decrease in water accessible surface area.•The latter causes a gain in translational entropy of water molecules.

It is shown that the contact-minimum configuration of two neopentane molecules is favoured on increasing hydrostatic pressure over the range 1-4000 atm, at room temperature, in line with the methane results (Graziano, 2014). This is due to the decrease in water accessible surface area accompanying the association, that leads to a gain in configurational/translational entropy of water molecules, whose magnitude increases with hydrostatic pressure. Of course, the strengthening of pairwise hydrophobic interaction cannot shed light on the pressure-induced denaturation of globular proteins.

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