Diffusive Dynamics of Nanoparticles in Arrays of Nanoposts

Kai He, Firoozeh Babaye Khorasani, Scott T. Retterer, Darrell K. Thomas, Jacinta C. Conrad, Ramanan Krishnamoorti

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


The diffusive dynamics of dilute dispersions of nanoparticles of diameter 200-400 nm were studied in microfabricated arrays of nanoposts using differential dynamic microscopy and single particle tracking. Posts of diameter 500 nm and height 10 μm were spaced by 1.2-10 μm on a square lattice. As the spacing between posts was decreased, the dynamics of the nanoparticles slowed. Moreover, the dynamics at all length scales were best represented by a stretched exponential rather than a simple exponential. Both the relative diffusivity and the stretching exponent decreased linearly with increased confinement and, equivalently, with decreased void volume. The slowing of the overall diffusive dynamics and the broadening distribution of nanoparticle displacements with increased confinement are consistent with the onset of dynamic heterogeneity and the approach to vitrification. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)5122-5130
Number of pages9
JournalACS Nano
Issue number6
StatePublished - May 20 2013
Externally publishedYes


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