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Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties

[Image: see text] Modifying the surfaces of metal nanoparticles with self-assembled monolayers of functionalized thiols provides a simple and direct method to alter their surface properties. Mixed self-assembled monolayers can extend this approach since, in principle, the surfaces can be tuned by al...

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Autores principales: Stewart, Alan, Zheng, Shuai, McCourt, Maighréad R., Bell, Steven E. J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2012
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614020/
https://www.ncbi.nlm.nih.gov/pubmed/22500816
http://dx.doi.org/10.1021/nn300629z
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author Stewart, Alan
Zheng, Shuai
McCourt, Maighréad R.
Bell, Steven E. J.
author_facet Stewart, Alan
Zheng, Shuai
McCourt, Maighréad R.
Bell, Steven E. J.
author_sort Stewart, Alan
collection PubMed
description [Image: see text] Modifying the surfaces of metal nanoparticles with self-assembled monolayers of functionalized thiols provides a simple and direct method to alter their surface properties. Mixed self-assembled monolayers can extend this approach since, in principle, the surfaces can be tuned by altering the proportion of each modifier that is adsorbed. However, this works best if the composition and microstructure of the monolayers can be controlled. Here, we have modified preprepared silver colloids with binary mixtures of thiols at varying concentrations and modifier ratios. Surface-enhanced Raman spectroscopy was then used to determine the effect of altering these parameters on the composition of the resulting mixed monolayers. The data could be explained using a new model based on a modified competitive Langmuir approach. It was found that the composition of the mixed monolayer only reflected the ratio of modifiers in the feedstock when the total amount of modifier was sufficient for approximately one monolayer coverage. At higher modifier concentrations the thermodynamically favored modifier dominated, but working at near monolayer concentrations allowed the surface composition to be controlled by changing the ratios of modifiers. Finally, a positively charged porphyrin probe molecule was used to investigate the microstructure of the mixed monolayers, i.e., homogeneous versus domains. In this case the modifier domains were found to be <2 nm.
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spelling pubmed-36140202013-04-03 Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties Stewart, Alan Zheng, Shuai McCourt, Maighréad R. Bell, Steven E. J. ACS Nano [Image: see text] Modifying the surfaces of metal nanoparticles with self-assembled monolayers of functionalized thiols provides a simple and direct method to alter their surface properties. Mixed self-assembled monolayers can extend this approach since, in principle, the surfaces can be tuned by altering the proportion of each modifier that is adsorbed. However, this works best if the composition and microstructure of the monolayers can be controlled. Here, we have modified preprepared silver colloids with binary mixtures of thiols at varying concentrations and modifier ratios. Surface-enhanced Raman spectroscopy was then used to determine the effect of altering these parameters on the composition of the resulting mixed monolayers. The data could be explained using a new model based on a modified competitive Langmuir approach. It was found that the composition of the mixed monolayer only reflected the ratio of modifiers in the feedstock when the total amount of modifier was sufficient for approximately one monolayer coverage. At higher modifier concentrations the thermodynamically favored modifier dominated, but working at near monolayer concentrations allowed the surface composition to be controlled by changing the ratios of modifiers. Finally, a positively charged porphyrin probe molecule was used to investigate the microstructure of the mixed monolayers, i.e., homogeneous versus domains. In this case the modifier domains were found to be <2 nm. American Chemical Society 2012-04-13 2012-05-22 /pmc/articles/PMC3614020/ /pubmed/22500816 http://dx.doi.org/10.1021/nn300629z Text en Copyright © 2012 American Chemical Society
spellingShingle Stewart, Alan
Zheng, Shuai
McCourt, Maighréad R.
Bell, Steven E. J.
Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties
title Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties
title_full Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties
title_fullStr Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties
title_full_unstemmed Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties
title_short Controlling Assembly of Mixed Thiol Monolayers on Silver Nanoparticles to Tune Their Surface Properties
title_sort controlling assembly of mixed thiol monolayers on silver nanoparticles to tune their surface properties
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614020/
https://www.ncbi.nlm.nih.gov/pubmed/22500816
http://dx.doi.org/10.1021/nn300629z
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