Stable Oxide Nanoparticle Clusters Obtained by Complexation

TL;DR

This paper demonstrates the formation of stable oxide nanoparticle clusters through electrostatic complexation with polyelectrolyte-neutral copolymers, revealing insights into their structure and size distribution.

Contribution

It introduces a method to create stable nanoparticle clusters using electrostatic complexation and visualizes their structure with cryo-electron microscopy.

Findings

Clusters range from 20 to 100 nm in size.

Particles are linked by adsorbed polyelectrolyte blocks.

Evidence of a polymer brush around clusters.

Abstract

We report on the electrostatic complexation between polyelectrolyte-neutral copolymers and oppositely charged 6 nm-crystalline nanoparticles. For two different dispersions of oxide nanoparticles, the electrostatic complexation gives rise to the formation of stable nanoparticle clusters in the range 20 - 100 nm. It is found that inside the clusters, the particles are pasted together by the polyelectrolyte blocks adsorbed on their surface. Cryo-transmission electronic microscopy allows to visualize the clusters and to determine the probability distributions functions in size and in aggregation number. The comparison between light scattering and cryo-microscopy results suggests the existence of a polymer brush around the clusters.