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Investigation of the Core−Shell Interface in Gold@Silica Nanoparticles: A Silica Imprinting Approach

Poovarodom, Saran and Bass, John D. and Hwang, Son-Jong and Katz, Alexander (2005) Investigation of the Core−Shell Interface in Gold@Silica Nanoparticles: A Silica Imprinting Approach. Langmuir, 21 (26). pp. 12348-12356. ISSN 0743-7463. doi:10.1021/la052006d.

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The nature of the self-assembled core−shell interface in gold@silica nanoparticles synthesized via a 3-aminopropyltrimethoxysilane (APTMS) route is investigated using materials synthesis as a sensitive tool for elucidating interfacial composition and organization. Our approach involves condensation of the gold@silica nanoparticles within a silica framework for synthesis of a composite gold−silica material containing ∼30 wt % gold. This material contains one of the highest gold loadings reported, but maintains gold core isolation as ascertained via a single surface plasmon resonance absorption band frequency corresponding to that of gold nanoparticles in dilute aqueous solution. The immobilized gold cores are subsequently etched using cyanide anion for the synthesis of templated porosity, which corresponds to the space that was occupied by the gold. Characterization of immobilized amines is performed using probe molecule binding experiments, which demonstrate a lack of accessible amines after gold removal. Solid-state 13C CPMAS NMR spectroscopy on these materials demonstrates that the amount of amine immobilization must be less than 10% of the expected yield, assuming that all of the APTMS becomes bound to the gold nanoparticle template. These results require a core−shell interface in the gold@silica nanoparticles that is predominantly occupied by inorganic silicate species, such as Si−O−Si and Si−OH, rather than primary amines. Such a result is likely a consequence of the weak interaction between primary amines and gold in aqueous solution. Our method for investigating the core−shell interface of gold@silica nanoparticles is generalizable for other interfacial structures and enables the synthesis of bulk imprinted silica using colloidal templates.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Hwang, Son-Jong0000-0002-3210-466X
Katz, Alexander0000-0003-3487-7049
Additional Information:© 2005 American Chemical Society. Received 23 July 2005. Published online 24 November 2005. Published in print 1 December 2005. The authors are grateful to Ms. Rina Zalpuri at the EML facility at UCB for providing helpful assistance with TEM experiments, and to Mr. Steven Ruzin at the Light Microscopy Facility at UCB for technical assistance with optical microscopy. The authors acknowledge the National Science Foundation (DMR 0444761) and a 3M Untenured Faculty Award for funding.
Funding AgencyGrant Number
NSFDMR 0444761
Issue or Number:26
Record Number:CaltechAUTHORS:20170725-072342350
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Official Citation:Investigation of the Core−Shell Interface in Gold@Silica Nanoparticles:  A Silica Imprinting Approach Saran Poovarodom, John D. Bass, Son-Jong Hwang, and Alexander Katz Langmuir 2005 21 (26), 12348-12356 DOI: 10.1021/la052006d
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79313
Deposited By: Ruth Sustaita
Deposited On:25 Jul 2017 16:30
Last Modified:15 Nov 2021 17:47

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