Figure 6
The free energy change due to gas capillary formation evaluated from the integral of the force-distance curve ∫FdD measured on retraction (solid black line) compared to the surface tension-area work ΔGγA calculated using Eq. (1) (blue symbols) for measurements in (a) water, (b) ethylene glycol and (c) hexadecane. The piezo expansion rate was 0.2 µm s−1. The pressure difference across capillary gas–liquid interface ΔP calculated from the difference between ∫FdD and ΔGγA in (a–c) as \(\Delta P=-\frac{\int F\mathrm{d}D-\Delta {G}_{\mathrm{\gamma A}}}{V}\), where V is the capillary volume in (d) water, (e) ethylene glycol and (f) hexadecane.
