Correlation of effective dispersive and polar surface energies in heterogeneous self-assembled monolayer coatings

We show, theoretically, that the measured effective dispersive and polar surface energies of a heterogeneous surface are correlated; the correlation, however, differs whether a Cassie or an Israelachvili and Gee model is assumed. Fluorocarbon self-assembled monolayers with varying coverage were grown on oxidized (100) silicon surfaces in a vapor phase process using five different precursors. Experimentally, effective surface energy components of the fluorocarbon self-assembled monolayers were determined from measured contact angles using the Owens-Wendt-Rabel-Kaelble method. We show that the correlation between the effective surface energy components of the heterogeneous surfaces coated with fluorocarbon self-assembled monolayers is in agreement with the Cassie model.