Symmetry breaking in self-assembled monolayers on solid surfaces: Anisotropic surface stress

This paper models the self-assembly dynamics of a two-phase monolayer on an elastic substrate. The two phases coarsen to reduce the phase boundary energy and refine to reduce the elastic energy. To minimize the total free energy, the two phases can order into nanoscale patterns. We combine the continuum phase field model of spinodal decomposition and the anisotropic surface stress. The numerical simulation shows various patterns, such as interwoven stripes, parallel stripes, triangular lattice of dots, and herringbone structures. The surface stress anisotropy causes a transition from the parallel stripes to the herringbone structures. We show that this symmetry breaking mesophase transition obeys the classical theory of Landau.