Tapping-mode force spectroscopy using cantilevers with interferometric high-bandwidth force sensors

Abstract

We quantitatively map the surface forces and elastic modulus in tapping-mode atomic force microscopy (AFM). To achieve this, we use custom-built cantilevers with interferometric high-bandwidth force sensors that can resolve nonlinear tip-sample interaction forces, combined with a set of algorithms to process the force sensor signals in real-time. Our technique achieves quantitative mechanical measurements, while retaining nanoscale spatial resolution and minimal loading forces in tapping-mode AFM. Moreover, conventional tapping-mode AFM images are not affected and can simultaneously be acquired. As a practical demonstration, we use our technique to quantify the mechanical properties of a polystyrene and linear low-density polyethylene blend.