Nanoscale mechanical characterization of PMMA by AFM nanoindentation: a theoretical study on the time-dependent viscoelastic recovery

Temperature-dependent indent recovery of polymethyl methacrylate is depicted by atomic force microscopy. The viscoelastic indent recovery is predicted by a numerical model based on the Boussinesq elastic theory. From the perspective of an elastic solution, viscoelastic solution for stress and displacement field is constructed through the analysis of the elasticity–viscoelasticity corresponding theory. The findings also illustrate the effect of loading condition, elastic modulus, and viscosity on the viscoelastic recovery rate.