Figure 6.

Force vs distance profile for one cluster formation. The repulsive force component starts at x ≈ 70 nm and ends at x ≈ 30 nm (x is the distance to the interface) where an attraction is observed. The top inset shows the calculated oscillating dielectric permittivity profile. Observe that for the interval x ≅ 5 nm up to x ≈ 35 nm the dielectric permittivity is ε_int ≥ 7, which corresponds in eq 1 to an attraction, and for x ≥ 35, ε is lower than 7, resulting in repulsive force acting on the tip.