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Proceedings Paper

Controlling nanoparticle aggregation in colloidal microwave absorbers via interface chemistry
Author(s): Brian A. Larsen; Michael A Haag; Michael H. B. Stowell; David C. Walther; Albert P. Pisano; Conrad R. Stoldt
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Paper Abstract

Interface chemistry can be implemented to modulate the aggregation and dispersion of nanoparticles in a colloidal solution. In this experimental study, we demonstrate the controlled aggregation of superparamagnetic magnetite nanoparticles in organic and aqueous solutions. With decrease in solution pH, individual nanoparticles (12-14 nm) reproducibly cluster to form ~52 nm monodisperse aggregates in toluene. Spin-spin (T2) proton relaxation measurements of the micellated clusters before and after aggregation show a change in the molar relaxation rate from 303 sec-1mol-1 to 368 sec-1mol-1 for individual and clustered nanoparticles, respectively. DNA-mediated aggregation of micellated nanoparticles in the colloidal solution is also demonstrated where the number of single-stranded DNA per particle determines the ultimate size of the nanoparticle aggregate.

Paper Details

Date Published: 27 April 2007
PDF: 8 pages
Proc. SPIE 6525, Active and Passive Smart Structures and Integrated Systems 2007, 652519 (27 April 2007); doi: 10.1117/12.715911
Show Author Affiliations
Brian A. Larsen, Univ. of Colorado, Boulder (United States)
Michael A Haag, Univ. of Colorado, Boulder (United States)
Michael H. B. Stowell, Univ. of Colorado, Boulder (United States)
David C. Walther, Univ. of California, Berkeley (United States)
Albert P. Pisano, Univ. of California, Berkeley (United States)
Conrad R. Stoldt, Univ. of Colorado, Boulder (United States)


Published in SPIE Proceedings Vol. 6525:
Active and Passive Smart Structures and Integrated Systems 2007
Yuji Matsuzaki; Mehdi Ahmadian; Donald J. Leo, Editor(s)

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