Nanoparticle formation utilizing simple polyacrylic acid-cation coacervates as template

TL;DR

Researchers developed a simple method to create nanoparticles using coacervates formed from polyacrylic acid and transition metal cations.

Contribution

A novel coacervate-mediated process is introduced for synthesizing transition metal carbonate/sulfide/oxide nanoparticles using only PAA, TM chloride, and carbonate/sulfide.

Findings

Coacervates of PAA and transition metals (Co, Mn, Ni, Cu) can be mineralized into small nanoparticles.

The method allows for calcination of carbonate particles into corresponding oxides.

Primary particles are small (5 nm) and amorphous, suggesting potential as catalysts.

Abstract

The liquid–liquid phase separation (coacervation) of simple solutions containing only polyacrylic acid (PAA) and multivalent transition metal (TM) cations can be used as a template for nanoparticle formation. It is shown that transition metal carbonate/sulfide/oxide nanoparticles can be prepared by a simple coacervate-mediated process using only PAA, the transition metal chloride, and either sodium carbonate or sulfide. The rather simple approach first demonstrated for calcium carbonate could be extended to the chosen transition metals Co, Mn, Ni, and Cu. Using DLS and UV/vis, the formation and properties of PAA/TM coacervates were studied showing that in a broad pH range, coacervation is possible when a critical cation concentration is reached. Using these findings, mineralization of the coacervates results in defined small nanoparticles that can be easily separated from other bigger residues. Calcination of carbonate particles results in their respective oxide counterparts. The rather small sizes (5 nm) of the primary particles and their amorphous crystal structure suggest further investigation into their use as catalysts.

Investigation on the formation of simple transition-metal polyacrylic acid coacervates and their use as a template for the synthesis of sulfide/carbonate/oxide nanoparticles.

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