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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