Mechanical characterization of polymers on a nanoscale through AFM nanoindentation: A theoretical study on the time-dependent viscoelastic recovery

The temperature-dependent indent recovery of polymer materials was measured by atomic force microscopy (AFM). A numerical model based on the Boussinesq equations was developed to simulate the viscoelastic indent recovery. Viscoelastic solution of stress and displacement is obtained by using the corresponding principle between elasticity and viscoelasticity. The numerical solution provides results that illustrate the influence of the loading conditions, elastic modulus and viscosity of the materials on the recovery rate of indentation. It provides a sound basis for prediction of deformation recovery on the polymer surface.