Quantification of nanoparticles' concentration inside polymer films using lock-in thermography

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Nanocomposite polymer films with nanoparticles are key for sensors and artificial skin.
• Characterizing these films requires advanced methods for composition and nanoparticle distribution analysis.
• Lock-in thermography (LIT) is an emerging non-destructive technique for thermal signature analysis.

Purpose of the Study:

• To demonstrate the use of lock-in thermography (LIT) for quantifying gold nanoparticle concentrations in polyvinyl alcohol (PVA) films.
• To develop a mathematical model correlating LIT measurements to nanoparticle concentration and distribution.
• To explore LIT's capability in detecting concentration gradients within thin films.

Main Methods:

• Preparation of thin PVA films with varying concentrations of gold nanoparticles (two sizes).
• Illumination of films with monochromatic light near the plasmonic resonance of gold nanoparticles.
• Measurement of thermal signature amplitude using LIT across multiple modulation frequencies.
• Development of a mathematical model to quantify nanoparticle concentration from thermal amplitude data.

Main Results:

• Successful quantification of gold nanoparticle concentration in PVA films using LIT.
• Demonstration of LIT's ability to detect and analyze concentration gradients within the films.
• Establishment of a quantitative relationship between LIT signal amplitude and nanoparticle concentration.
• Discussion on determining sample thickness using LIT.

Conclusions:

• Lock-in thermography is a reliable, non-destructive method for quantifying nanoparticle concentrations in polymer nanocomposites.
• LIT provides valuable insights into the spatial distribution of nanoparticles, essential for material design.
• This technique offers a novel approach for characterizing advanced functional materials.