Growth dynamics for DNA-Guided nanoparticle crystallization

Subas Dhakal, Kevin Lee Kohlstedt, George C Schatz, Chad A Mirkin, M Olvera de la Cruz*

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Spherical nucleic acid (SNA) nanostructures assemble into a large variety of well-defined crystalline superlattices via DNA-directed hybridization. Crystallities of SNA with various shapes emerge during the assembly process, which coalesce during coarsening, leading to polycrystalline materials. Here, we investigate the growth dynamics of SNAs into body-centered cubic superlattices and the coalescence of SNA aggregates using a colloidal model formulated from the competition of electrostatic core repulsions and localized DNA hybridization attractions. We find that the growth law of isolated SNA crystallities is well-described by the power law t1/2, in agreement with experimental observations. At later times, coalescence slows the growth dynamics considerably and is dependent on the orientational mismatch (misorientation angle) of the coalescing crystallites. Molecular dynamics simulations show that the misorientation angle decreases continually during the coalescence, which is a signature of the grain rotation induced coalescence mechanism. This mechanism is followed by the coarsening of a "neck" that develops at the boundary between the coalescing crystallites. Remarkably, we find faster coalescence dynamics for larger SNAs compared to smaller SNAs due to their enhanced surface diffusion, which more effectively reduces curvature at the boundary of two superlattices. These findings provide fundamental insight into the relationship between nanoparticle surface chemistry and its crystallite growth and coalescence.

Original languageEnglish (US)
Pages (from-to)10948-10959
Number of pages12
JournalACS nano
Volume7
Issue number12
DOIs
StatePublished - Dec 23 2013

Keywords

  • DNA-functionalized
  • colloids
  • crystallization kinetics
  • grain boundaries
  • nanoscale materials
  • synthons

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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