Viscoelastic property mapping with contact resonance force microscopy.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Understanding near-surface viscoelastic properties is crucial for polymer blend performance.
• Traditional methods often lack the nanoscale resolution required for detailed characterization.

Purpose of the Study:

• To demonstrate accurate nanoscale mapping of viscoelastic properties (loss and storage moduli) in a polystyrene-polypropylene blend.
• To evaluate two data acquisition methods: discrete stepping and continuous scanning.

Main Methods:

• Utilized contact resonance force microscopy (CR-FM) to probe viscoelasticity.
• Extracted spatially resolved maps of contact resonance frequency and quality factor from the AFM cantilever.
• Compared CR-FM data with dynamic mechanical analysis (DMA) measurements.

Main Results:

• Achieved accurate nanoscale mapping of near-surface loss and storage moduli.
• Demonstrated good agreement between CR-FM and time-temperature superposition of DMA for point mapping and low-speed scanning.
• Validated the ability to correlate low-frequency DMA with high-frequency CR-FM measurements.

Conclusions:

• CR-FM is a powerful technique for nanoscale viscoelastic property mapping of polymer blends.
• The data acquisition method impacts the accuracy and agreement with lower-frequency measurements.
• CR-FM provides valuable insights into the heterogeneous mechanical behavior of polymer blends at the nanoscale.