Quantitative Contact Resonance Force Microscopy for Viscoelastic Measurement of Soft Materials at the Solid-Liquid...

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Viscoelastic property measurements are crucial for material characterization in biological and industrial applications.
• Nanostructured materials necessitate nanoscale measurement techniques.
• Existing nanoscale contact resonance force microscopy (CR-FM) methods face challenges in liquid environments due to spurious signals and difficulty separating sample effects from environmental factors.

Purpose of the Study:

• To develop a method for accurate nanoscale viscoelastic measurements at the solid-liquid interface.
• To overcome confounding liquid effects in CR-FM measurements.
• To enable quantitative characterization of material mechanical properties in liquid.

Main Methods:

• Utilized photothermal cantilever excitation in multiple resonance modes.
• Applied a predictive model for hydrodynamic effects to mitigate liquid interference.
• Extracted material loss tangents (tan δ) from CR-FM data.

Main Results:

• Successfully demonstrated quantitative, nanoscale viscoelastic CR-FM measurements at the solid-liquid interface.
• Validated the technique on polymer samples and a plant cell wall.
• Observed agreement in tan δ values between measurements in water and air for certain polymers (polystyrene) and all conditions for polypropylene.

Conclusions:

• The developed CR-FM technique enables reliable nanoscale viscoelastic measurements in liquid.
• This advancement is significant for characterizing polymers and biological materials at interfaces.
• The method provides a pathway for more accurate material property analysis in diverse liquid environments.