Atomic force microscopy (AFM) can be used for both imaging and force measurements of samples. The AFM tip is attached to a cantilever and scanned across the sample surface in a raster pattern, generating a topographic map of the sample surface. During the scanning process, the force between the tip and the sample is measured by the deflection of the cantilever. This force can be used to perform force measurements on the sample.
The imaging capabilities of AFM are highly dependent on the imaging mode used. In contact mode, the tip is in constant contact with the surface, and the deflection of the cantilever is used to maintain a constant force between the tip and the sample. This allows for high-resolution imaging of the surface topography of the sample. In tapping mode, the tip interacts with the surface intermittently, which can reduce the amount of damage done to the sample during imaging. Non-contact mode involves the tip being held a short distance away from the surface, and the interaction between the tip and the sample is measured using a feedback loop to maintain a constant distance between the tip and the sample.
In addition to imaging, AFM can also be used to measure the mechanical properties of a sample. Force measurements can be performed by applying a force to the sample and measuring the resulting deformation or movement of the sample. This can provide information about the stiffness, elasticity, and adhesion properties of the sample.
Overall, AFM is a highly versatile tool that can be used for both imaging and force measurements of a wide range of samples, from biological molecules to materials.
