where q was the charge of particles i or j, erf c() is the complementary error-function, α is the damping parameter and r c is the cutoff distance of Coulombic interactions. The cutoff distance was set to a value of r c = 12 Å and the damping parameter was set to a value of α = 0.2 Å-1 . LJ and Coulombic interactions were gradually switched off, by scaling λ from λ = 1 for fully coupled solid-liquid interactions, to λ ≈ 0 for fully uncoupled solidliquid interactions. The coupling parameter was not sampled at λ = 0 to avoid numerical instability that may arise when solid-liquid interactions are entirely decoupled. Values for λ = 0 were extrapolated from the two nearest data points. The work of adhesion could be obtained using the equation: