Visualization of Au Nanoparticles Buried in a Polymer Matrix by Scanning Thermal Noise Microscopy

TL;DR

This paper demonstrates a novel method using scanning thermal noise microscopy to visualize buried gold nanoparticles within a polymer matrix by detecting changes in contact stiffness and damping.

Contribution

The study introduces a new application of thermal noise spectrum measurement for subsurface nanoparticle visualization in polymers.

Findings

Au nanoparticles buried 300 nm can be detected

Contact stiffness variation correlates with nanoparticle presence

Technique exceeds traditional depth range limitations

Abstract

We demonstrated visualization of Au nanoparticles buried 300 nm into a polymer matrix by measurement of the thermal noise spectrum of a microcantilever with a tip in contact to the polymer surface. The subsurface Au nanoparticles were detected as the variation in the contact stiffness and damping reflecting the viscoelastic properties of the polymer surface. The variation in the contact stiffness well agreed with the effective stiffness of a simple one-dimensional model, which is consistent with the fact that the maximum depth range of the technique is far beyond the extent of the contact stress field.