Nanoparticle Interactions Guided by Shape-Dependent Hydrophobic Forces

Shu Fen Tan, Sanoj Raj, Geeta Bisht, Harshini V. Annadata, Christian A. Nijhuis, Petr Kral, Utkur Mirsaidov*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

20 Citations (Scopus)

Abstract

Self‐assembly of solvated nanoparticles (NPs) is governed by numerous competing interactions. However, relatively little is known about the time‐dependent mechanisms through which these interactions enable and guide the nanoparticle self‐assembly process. Here, using in situ transmission electron microscopy imaging combined with atomistic modeling, it is shown that the forces governing the self‐assembly of hydrophobic nanoparticles change with the nanoparticle shapes. By comparing how gold nanospheres, nanocubes, nanorods, and nanobipyramids assemble, it is shown that the strength of the hydrophobic interactions depends on the overlap of the hydrophobic regions of the interacting nanoparticle surfaces determined by the nanoparticle shapes. Specifically, this study reveals that, in contrast to spherical nanoparticles, where van der Waals forces play an important role, hydrophobic interactions can be more relevant for nanocubes with flat side faces, where an oriented attachment between the nanocubes is promoted by these interactions. The attachment of nanocubes is observed to proceed in two distinct pathways: nanocubes either: (i) prealign their faces before the attachment, or (ii) first connect through a misaligned (edge‐to‐edge) attachment, followed by a postattachment alignment of their faces. These results have important implications for understanding the interaction dynamics of NPs and provide the framework for the design of future self‐assembled nanomaterials.
Original languageEnglish
Article number1707077
JournalAdvanced materials
Volume30
Issue number16
DOIs
Publication statusPublished - 19 Apr 2018
Externally publishedYes

Keywords

  • hydrophobic interactions
  • in situ transmission electron microscopy
  • nanoparticles
  • self-assembly
  • van der Waals forces

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