Stability and electrostatics of mercaptoundecanoic acid-capped gold nanoparticles with varying counterion size

Timo Laaksonen, Päivi Ahonen, Christoffer Johans, Kyösti Kontturi

    Research output: Contribution to journalArticleScientificpeer-review

    99 Citations (Scopus)

    Abstract

    The solubility of charged nanoparticles is critically dependent on pH. However the concentration range available with bases such as NaOH is quite narrow, since the particles precipitate due to compression of the electric double layer when the ionic strength is increased. The stability of mercaptoundecanoic acid-capped Au nanoparticles is studied at a set pH using the hydroxide as base and different cations Of Various sizes. The counterions used are sodium (Na+), tetramethylammonium (TMA(+)), tetraethylammonium (TEA(+)), and tetrabutylammonium (TBA(+)). The particles precipitate in the 70-90 mm range with Na+ as the counterion, but with quaternary ammonium hydroxides the particles are stable even in concentrations exceeding I m. The change in solubility is linked to a strongly adsorbed layer on the surface of the ligand shell of the nanoparticles. The increased concentration range obtained with TEAOH is further used to facilitate thiol exchange which occurs at a greater extent than would be achieved in NaOH solution.

    Original languageEnglish
    Pages (from-to)2143-2149
    Number of pages7
    JournalChemPhysChem
    Volume7
    Issue number10
    DOIs
    Publication statusPublished - 13 Oct 2006
    MoE publication typeA1 Journal article-refereed

    Keywords

    • colloids
    • gold
    • ligand effects
    • nanostructures
    • surface chemistry
    • SPHERICAL COLLOIDAL PARTICLE
    • ELECTROPHORETIC MOBILITY
    • CLUSTER MOLECULES
    • DOUBLE-LAYER
    • SPHERES

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