Comments on the use of the A.F.M. in the contact mode for polymer films

Summary form only given. Atomic Force Microscopy has been described as a powerful technique for studying insulating, hard, surface. Since then, it is also considered as an appropriate technique for investigating at a submicromic scale elastic and viscoelastic properties of soft material as polymer films. Here we show that macroscopic models, namely Hertz, Johnson Kendall Roberts and Maugis-Barquins ones, can be fruitfully employed. With this continuum approach, we interpret either the roughness observed with the topographical mode or the force curves obtained in A.F.M. for polymer films. Finally this approach should allow to clarify the conditions for which the macroscopic approach fails.