360° multiparametric imaging atomic force microscopy: A method for three-dimensional nanomechanical mapping.

Atomic Force Microscopy (AFM) has been intensively used for imaging, characterization and manipulation at the micro- and nanoscale. Taking into account that the material is usually anisotropic, it needs to be characterized in various regions and orientations. Although recent advances of AFM techniques have allowed for large area scan of the sample on a two-dimensional plane, mapping a three-dimensional (3D) sample at a full orientation of 360° remains challenge. This paper reports a multiparametric imaging atomic force microscope via robot technique for 360° mapping and 3D reconstruction of the sample's topography and nanomechanical properties. The system is developed by integrating a three degrees of freedom (DoFs) high-precision rotation stage and a home positioning approach is proposed to compensate for the eccentric distance between the cross-section center of the sample and the ration center of the stage. With this method, the sample surface can be fully mapped by the force-distance-based AFM via rotating the sample with a complete orientation. 360° multiparametric mapping and 3D reconstruction results (e.g., topography, adhesion, modulus, energy dissipation) of a human hair demonstrate practicability and reliability of the proposed method.