Diffusive Dynamics of Nanoparticles in Arrays of Nanoposts

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

Diffusive Dynamics of Nanoparticles in Arrays of Nanoposts

Type

Article

Authors

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

KAUST Grant Number

KUS-C1-018-02

Online Publication Date

2013-05-20

Print Publication Date

2013-06-25

Date

2013-05-20

Abstract

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.

Citation

He K, Babaye Khorasani F, Retterer ST, Thomas DK, Conrad JC, et al. (2013) Diffusive Dynamics of Nanoparticles in Arrays of Nanoposts. ACS Nano 7: 5122–5130. Available: http://dx.doi.org/10.1021/nn4007303.

Acknowledgements

This publication is based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). R.K. and K.H. acknowledge the partial support of the Gulf of Mexico Research Initiative (Consortium for Ocean Leadership Grant SA 12-05/GoMRI-002). J.C.C. is supported by the American Chemical Society Petroleum Research Fund (52537-DNI7) and the National Science Foundation (DMR-1151133). A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.