Formation of Single-Digit Nanometer Scale Silica Nanoparticles by Evaporation-Induced Self-Assembly

Shigeru Sakamoto, Masashi Yoshikawa, Kota Ozawa, Yoshiyuki Kuroda, Atsushi Shimojima, Kazuyuki Kuroda

    Research output: Contribution to journalArticle

    1 Citation (Scopus)

    Abstract

    There are emerging demands for single-digit nanoscale particles in multidisciplinary fields, such as nanomedicine, optics, catalysis, and sensors, to create new functional materials. Here, we report a novel route to prepare silica nanoparticles less than 3 nm in size via the evaporation-induced self-assembly of silicate species and quaternary trialkylmethylammonium surfactants, which usually form reverse micelles. The solvent evaporation induces a local concentration increase and simultaneous polycondensation of silicate species within the hydrophilic region of the surfactant mesophases. Extremely small silica nanoparticles in the silica-surfactant mesostructures can be stably dispersed in organic solvents by destroying the mesostructure, which is in clear contrast to the preparation of silica nanoparticles using the conventional reverse micelle method. The surface chemical modification of the formed silica nanoparticles is easily performed by trimethylsilylation. The particle size is adjustable by changing the ratio of the surfactants to the silica source because the hydrophobic/hydrophilic ratio determines the curvature and diameter of the resulting spherical silica-surfactant domains in the mesostructure. The versatility of this method is demonstrated by the fabrication of very small titania nanoparticles. These findings will increase the designability of oxide nanoparticles at the single-digit nanoscale because conventional methods based on the generation and growth of nuclei in a solution cannot produce such nanoparticles with highly regulated sizes.

    Original languageEnglish
    Pages (from-to)1711-1717
    Number of pages7
    JournalLangmuir
    Volume34
    Issue number4
    DOIs
    Publication statusPublished - 2018 Jan 30

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics
    • Surfaces and Interfaces
    • Spectroscopy
    • Electrochemistry

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