Influence of surface energy inhomogeneity on contact adhesion: simulation and experiment

The paper presents simulation data on the indentation of a rigid indenter with an inhomogeneous surface energy into an elastic half-space, showing that the surface energy distribution has a critical effect on the contact properties. The data include dependences of the average normal force and contact radius on the indentation depth, obtained by averaging a large number of random surface energy distributions, and 3D probability density functions of these quantities. Also presented are experimental data on the indentation of a steel indenter with chemically inhomogeneous surface properties into an elastic sheet of transparent rubber, allowing one to judge the evolution of the contact force and contact configuration. The experimental data show that the surface energy distribution has hardly any effect on the contact properties during indentation and has a strong effect on the behavior of the system during separation. The simulation and experimental data agree qualitatively