1. Chemical Identity of Poly(N-vinylpyrrolidone) End Groups Impact Shape Evolution During the Synthesis of Ag Nanostructures
- Author
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Justin Anderson, Suprita Jharimune, Rueben Pfukwa, Bert Klumperman, Zhifeng Chen, and Robert M. Rioux
- Subjects
chemistry.chemical_classification ,Reducing agent ,technology, industry, and agriculture ,N-Vinylpyrrolidone ,Nanoparticle ,macromolecular substances ,General Chemistry ,Polymer ,Biochemistry ,Catalysis ,Solvent ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Monomer ,chemistry ,Chemical engineering ,Polyol ,Ethylene glycol - Abstract
Ag nanocubes (AgNCs) are predominantly synthesized by the polyol method, where the solvent (ethylene glycol) is considered the reducing agent and poly(N-vinylpyrrolidone) (PVP) the shape-directing agent. An experimental phase diagram for the formation of Ag nanocubes as a function of PVP monomer concentration (Cm) and molecular weight (Mw) demonstrated end groups of PVP impact the final Ag product. Measured rates of the initial Ag+ reduction at different PVP Cm and Mw confirmed the reducing effect originates from end-groups. PVP with well-defined aldehyde and hydroxyl end groups lead to the formation of Ag nanocubes and nanowires respectively, indicating the faster reducing agent formed kinetically preferred nanowires. We demonstrate PVP end-groups induce initial reduction of Ag+ to form seeds followed by autocatalytic reduction of Ag+ by ethylene glycol (and not solvent oxidation products) to form Ag nanostructures. The current study enabled a quantitative description of the role of PVP in nanoparticle shape-control and demonstrates a unique opportunity to design nanostructures by combining nanoparticle synthesis with polymer design to introduce specific physicochemical properties.
- Published
- 2020
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