Nano-scale characterization of the formation of silver layers during electroless deposition on polymeric surfaces

TL;DR

This study introduces a TEM-based method to quantitatively analyze nanoparticle formation and morphology during silver electroless deposition on polymers, revealing how nanoparticle size and distribution influence layer formation.

Contribution

It provides a novel TEM technique for measuring nanoparticle shapes and sizes, and investigates how gold nanoparticle size affects silver layer formation on polymers.

Findings

Gold nanoparticles vary in size depending on reducing agents used.

Nanoparticles are found both on surface and below the polymer surface.

Silver layers' morphology is influenced by the size and distribution of gold nucleating agents.

Abstract

We report here a quantitative method of Transmission Electron Microscopy (TEM) to measure the shapes, sizes and volumes of nanoparticles which are responsible for their properties. Gold nanoparticles (Au NPs) acting as nucleating agents for the electroless deposition of silver NPs on SU-8 polymers were analyzed in this project. The atomic-number contrast (Z-contrast) imaging technique reveals the height and effective diameter of each Au NP and a volume distribution is obtained. Varying the reducing agents produced Au NPs of different sizes which were found both on the polymer surface and in some cases buried several nanometers below the surface. The morphology of Au NPs is an important factor for systems that use surface-bound nanoparticles as nucleation sites as in electroless metallization. Electrolessly deposited silver layers reduced by hydroquinone on SU-8 polymer are analyzed in this project.