Interaction Stress Measurement Using Atomic Force Microscopy: A Stepwise Discretization Method

Atomic force microscopy (AFM) is one of the most common techniques for interaction measurements. However, there are severe problems in attaining and interpreting the current interaction measurements obtained from AFM experiments. The existing procedures do not provide a clear understanding of the interaction mechanism and use misleading and ineffective evaluating criteria. Furthermore, ineffective experimental procedures neglect to use the full range of the AFM force curves for interaction measurement. To overcome the drawbacks of the currently used methods, the current work proposes a new interaction measurement parameter, called interaction stress. From the interaction stress, all other interaction properties, such as interaction force, interaction energy, and internal stress, can be calculated. In order to obtain the interaction stress from the AFM measurements, the details of a new method, a stepwise discretization method, are explained. Finally, a set of AFM experiments are designed and performed, and the results are presented in terms of interaction stress. The validity of the captured results is examined by using well established Hamaker constants. The good agreement between the results of the current work and the literature demonstrates the ability of the stepwise discretization method in capturing the interaction stress properly.