Localized Thermomechanical Measurements of Polymers and Blends with AFM-IR

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Understanding thermomechanical behavior is key for designing heterogeneous polymer systems.
• Existing methods may struggle with precise nanoscale thermal analysis of complex polymer structures.

Purpose of the Study:

• To develop and demonstrate a novel technique coupling chemistry-selective infrared (IR) heating with atomic force microscopy (AFM) nanomechanical measurements.
• To enable precise thermal characterization of heterogeneous polymer films at the nanoscale.

Main Methods:

• Utilized a novel technique combining IR laser heating with AFM nanomechanical measurements.
• Employed chemistry-selective IR heating based on material-specific absorption bands.
• Varied surface heating by adjusting the IR repetition rate.

Main Results:

• Demonstrated controlled melting of poly(ethylene glycol) (PEG) films across a range of molecular weights.
• Qualitatively detected the glass transition temperature of thickness-confined poly(lactic acid) (PLA) films.
• Successfully applied the technique to a PLA and nitrile butadiene rubber blend for phase-specific thermal characterization.

Conclusions:

• The coupled IR heating and AFM technique offers a powerful tool for probing thermomechanical properties of heterogeneous films.
• This method minimizes thermal drift, allows rapid heating with concurrent measurements, and circumvents bulk material changes.
• Paves a new avenue for nanoscale thermal analysis of complex polymer systems.