Figure 3.

Interfacial layer structure of organic liquids on hydrophobic silica surfaces. (a) 2D force maps (x, z) of a hydrophobic silica–heptane interface. (b) Force–distance curves obtained from the rectangle marked in panel (a). (c) 2D force maps (x, z) of a hydrophobic silica–pentadecane interface. (d) Force–distance curves obtained from panel (c). (e) Histogram of d₁ and d₂ distances measured on hydrophobic silica surfaces in heptane. (f) Histogram of d₁ and d₂ distances measured on hydrophobic silica surfaces in pentadecane. The average force–distance curve is highlighted in blue in (b) and (d). Individual force–distance curves are plotted in gray in (b) and (d). Experimental parameters for heptane (pentadecane): f = 590,776 (476,235) kHz, k = 8.2 N m^–1, Q = 5.4 (4.6), A₀ = 100 pm, and A_sp = 60 pm.