MAC Mode AFM for Precision Interfacial Force Measurements Application Note

About this manual

The document introduces a new approach to Atomic Force Microscopy (AFM) called MAC Mode, where force is applied directly to an AFM tip using a magnetic field rather than mechanical scanning. This method eliminates spurious resonances seen in fluid tapping mode and improves image quality.

The note details experiments measuring the ordering of liquid molecules at interfaces with graphite. Using OMCTS and mesitylene as test substances, the authors demonstrate that MAC Mode AFM provides highly reproducible data on molecular layering and spacing, consistent with known molecular dimensions.

What's inside

• Introduction to MAC Mode AFM
• Measurement of Surface Forces
• Liquid Ordering at Interfaces
• OMCTS Graphite Interface Analysis
• Mesitylene Graphite Interface Analysis
• Force Spectra Interpretation
• Young's Modulus Estimation

Specifications

Frequently asked questions

What advantage does MAC Mode offer over fluid tapping mode?

It eliminates spurious resonances seen in fluid tapping mode, leading to substantial improvements in image quality.

What is the typical spring constant for the MAClevers used in this setup?

The spring constant of the magnetically coated cantilevers was typically 0.5 nN/nm.

What is the range of tip oscillation frequency used for these measurements?

The tip oscillation frequency was set between 200 and 500 Hz.

What is the assumed radius of the AFM tip for calculating Young's modulus?

For the calculations, the radius of the tip was assumed to be 30 nm.