Depth mapping of metallic nanowire polymer nanocomposites by scanning dielectric microscopy

TL;DR

This paper demonstrates that Scanning Dielectric Microscopy (SDM) can non-destructively map the three-dimensional distribution of metallic nanowires within polymer nanocomposites, aiding their optimization for electronic applications.

Contribution

The study introduces a quantitative SDM method combined with finite-element calculations to determine nanowire depth distribution in nanocomposites.

Findings

SDM effectively maps nanowire distribution in nanocomposites.

The technique works under different humidity conditions.

It provides a non-destructive way to analyze subsurface nanostructures.

Abstract

Polymer nanocomposite materials based on metallic nanowires are widely investigated as transparent and flexible electrodes or as stretchable conductors and dielectrics for biosensing. Here we show that Scanning Dielectric Microscopy (SDM) can map the depth distribution of metallic nanowires within the nanocomposites in a non-destructive way. This is achieved by a quantitative analysis of sub-surface electrostatic force microscopy measurements with finite-element numerical calculations. As an application we determined the three-dimensional spatial distribution of around 50 nm diameter silver nanowires in 100 - 250 nm thick gelatin films. The characterization is done both under dry ambient conditions, where gelatin shows a relatively low dielectric constant, epsilon around 5, and under humid ambient conditions, where its dielectric constant increases up to epsilon around 14. The present results show that SDM can be a valuable non-destructive subsurface characterization technique for nanowire-based nanocomposite materials, which can contribute to the optimization of these materials for applications in fields such as wearable electronics, solar cell technologies or printable electronics.