Atomic force microscopy as a tool for mechanical characterizations at the nanometer scale

The design, optimization, and realization of innovative nanocomposite materials for advanced applications in a broad range of fields, from energy, automotive, photonics, to biology and nanomedicine require the capability to characterize their physical (e.g., mechanical, electric, magnetic...) properties from a multiscale perspective, in particular, not only at the macroscopic scale, but also at the nanometer one. In particular, methods are needed to characterize mechanical properties with nanometer lateral resolution, in order to understand the contribution of the nanosized features of the materials and the related phenomena. Atomic force microscopy (AFM) has been evolved from a tool for the morphological analysis of the sample surface to an integrated platform for the physicochemical characterization of samples. Current AFM systems host several advanced techniques for the mechanical characterization of materials with high speed and high lateral resolution in a broad range of mechanical moduli, e.g., from stiff samples (e.g., coatings, crystals…) to soft materials (e.g., polymers, biological samples...), in different environments (e.g., air, vacuum, liquid), and conditions (controlled humidity, controlled temperature). Here, short review of AFM based methods for the nanomechanical characterization of materials, in particular force spectroscopy, is reported, with emphasis on the materials which can be analyzed.