Nanoscale Mechanical Property Measurements in AFM Modes with Direct Force Control
Real-time control of the peak force of the tip-sample interaction with PeakForce Tapping has led to a fundamental change in atomic force microscopy (AFM), providing quantitative mapping of mechanical properties of soft materials at unprecedented resolution and speed while preserving the tip and sample. Force Volume, PeakForce Tapping and Contact Resonance (CR-AFM) can provide complimentary mechanical property information, covering a wide range of time-scales (seconds to microseconds) and accessing different properties and/or different ranges of properties. For example, PeakForce QNM and Force Volume work well with samples of modulus in the range of kPa up to a few tens of GPa, while CR-AFM can cover the range of a few GPa to hundreds of GPa. In some cases, the techniques can be combined for simultaneous results and improved stability.
In this talk, we will discuss improvements to the contact geometry analysis for CR-AFM with examples on various materials. We will also examine new developments combining CR-AFM with force-controlled modes such as force volume and PeakForce tapping. This provides new insights for contact mechanics and also into the mechanics of contact formation and contact breaking. Finally, we will consider the effect of the time dependence of material properties on all of the measurements.