Self-faceting of emulsion droplets as a route to solid icosahedra and other polyhedra

Orlando Marin, Maria Alesker, Shani Guttman, Gregory Gershinsky, Eitan Edri, Hagay Shpaisman, Rodrigo E. Guerra, David Zitoun, Moshe Deutsch, Eli Sloutskin

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Hypothesis: Temperature-controlled self-faceting of liquid droplets has been recently discovered in surfactant-stabilized alkane-in-water emulsions. We hypothesize that similar self-faceting may occur in emulsion droplets of UV-polymerizable linear hydrocarbons. We further hypothesize that the faceted droplet shapes can be fixed by UV-initiated polymerization, thus providing a new route towards the production of solid polyhedra. Experiments: Temperature-induced shape variations were studied by optical microscopy in micron-size emulsion droplets of UV-polymerizable alkyl acrylate. When polymerized, the resultant solid particles’ 3D shape and internal structure were determined by combined scanning electron microscopy (SEM) and focused ion beam (FIB) slicing. The SEM and FIB nanoscale resolution provided a far greater detail imaging than that achievable for the liquid droplets, which could only be studied by optical microscopy, severely limiting their 3D shape determination. Findings: We demonstrate the formation of solid icosahedra, polyhedral platelets, and rods of hitherto-unreported sizes, well below the 3D-printing resolution (∼20μm). The presence of icosahedral shapes and the absence of any resolvable internal structure at sub-μm length scales, are in line with the surface-freezing-driven mechanism proposed for the faceting phenomenon. Further development of the method presented here may allow large-quantity production of shaped micron- to nano- sized colloidal building blocks for 3D metamaterials and other applications.

Original languageEnglish
Pages (from-to)541-545
Number of pages5
JournalJournal of Colloid and Interface Science
Volume538
DOIs
StatePublished - 7 Mar 2019

Bibliographical note

Publisher Copyright:
© 2018 Elsevier Inc.

Keywords

  • Colloids
  • Emulsions
  • Faceting
  • Interfacial freezing
  • Polyhedral nanoparticles
  • Surface freezing

Fingerprint

Dive into the research topics of 'Self-faceting of emulsion droplets as a route to solid icosahedra and other polyhedra'. Together they form a unique fingerprint.

Cite this