Shaping micro-clusters via inverse jamming and topographic close-packing of microbombs

Seunggun Yu, Hyesung Cho, Jun Pyo Hong, Hyunchul Park, Jason Christopher Jolly, Hong Suk Kang, Jin Hong Lee, Junsoo Kim, Seung Hwan Lee, Albert S. Lee, Soon Man Hong, Cheolmin Park, Shu Yang, Chong Min Koo

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Designing topographic clusters is of significant interest, yet it remains challenging as they often lack mobility or deformability. Here we exploit the huge volumetric expansion (up to 3000%) of a new type of building block, thermally expandable microbombs. They consist of a viscoelastic polymeric shell and a volatile gas core, which, within structural confinement, create micro-clusters via inverse jamming and topographical close-packing. Upon heating, microbombs anchored in rigid confinement underwent balloon-like blowing up, allowing for dense clusters via soft interplay between viscoelastic shells. Importantly, the confinement is unyielding against the internal pressure of the microbombs, thereby enabling self-assembled clusters, which can be coupled with topographic inscription to introduce structural hierarchy on the clusters. Our strategy provides densely packed yet ultralight clusters with a variety of complex shapes, cleavages, curvatures, and hierarchy. In turn, these clusters will enrich our ability to explore the assemblies of the ever-increasing range of microparticle systems.

Original languageEnglish
Article number721
JournalNature communications
Issue number1
Publication statusPublished - 2017 Dec 1

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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