Reversible Supracolloidal Self-Assembly of Cobalt Nanoparticles to Hollow Capsids and Their Superstructures

Research output: Contribution to journalArticle


Research units

  • University of Jyväskylä
  • University of Helsinki


The synthesis and spontaneous, reversible supracolloidal hydrogen bond-driven self-assembly of cobalt nanoparticles (CoNPs) into hollow shell-like capsids and their directed assembly to higher order superstructures is presented. CoNPs and capsids form in one step upon mixing dicobalt octacarbonyl (Co2CO8) and p-aminobenzoic acid (pABA) in 1,2-dichlorobenzene using heating-up synthesis without additional catalysts or stabilizers. This leads to pABA capped CoNPs (core ca. 5nm) with a narrow size distribution. They spontaneously assemble into tunable spherical capsids (d≈50-200nm) with a few-layered shells, as driven by inter-nanoparticle hydrogen bonds thus warranting supracolloidal self-assembly. The capsids can be reversibly disassembled and reassembled by controlling the hydrogen bonds upon heating or solvent exchanges. The superparamagnetic nature of CoNPs allows magnetic-field-directed self-assembly of capsids to capsid chains due to an interplay of induced dipoles and inter-capsid hydrogen bonds. Finally, self-assembly on air-water interface furnishes lightweight colloidal framework films.


Original languageEnglish
Pages (from-to)6473–6477
JournalAngewandte Chemie
Issue number23
Publication statusPublished - 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • Capsids, Colloidal self-assembly, Electron tomography, Hydrogen bonding, Magnetic nanoparticles

Download statistics

No data available

ID: 13275435