Effect of pH on the final connectivity distribution of the silicon atoms in the Stöber particles

Kangtaek Lee; Alon McCormick

doi:10.1007/s10971-005-6374-y

Effect of pH on the final connectivity distribution of the silicon atoms in the Stöber particles

Kangtaek Lee, Alon McCormick

Department of Chemical and Biomolecular Engineering

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Using ²⁹Si MAS-NMR we investigate the effect of pH on the final connectivity distribution of the silicon atoms in the Stöber particles. Our data suggest that the fraction of the silicon atoms that are ully-connected decreases as the ammonia concentration is increased. This suggests a more negative first shell substitution effect in the precipitated phase (liquid droplet) if condensation reactions are irreversible. A simple model is developed to describe the condensation kinetics in the precipitated phase and the results support the negative first shell substitution effect. These findings challenge the notion of a positive first shell substitution effect in alkaline conditions.

Original language	English
Pages (from-to)	255-260
Number of pages	6
Journal	Journal of Sol-Gel Science and Technology
Volume	33
Issue number	3
DOIs	https://doi.org/10.1007/s10971-005-6374-y
Publication status	Published - 2005 Mar

Bibliographical note

Funding Information:
We acknowledge the support of the National Science Foundation (CTS-89 10423) and the Center for Interfacial Engineering at the University of Minnesota. KL acknowledges the support of the Korea Research Foundation (KRF-2003-005-D00001) and Yonsei University Research Fund of 2001.

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Ceramics and Composites
General Chemistry
Biomaterials
Condensed Matter Physics
Materials Chemistry

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10.1007/s10971-005-6374-y

Cite this

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title = "Effect of pH on the final connectivity distribution of the silicon atoms in the St{\"o}ber particles",

abstract = "Using 29Si MAS-NMR we investigate the effect of pH on the final connectivity distribution of the silicon atoms in the St{\"o}ber particles. Our data suggest that the fraction of the silicon atoms that are ully-connected decreases as the ammonia concentration is increased. This suggests a more negative first shell substitution effect in the precipitated phase (liquid droplet) if condensation reactions are irreversible. A simple model is developed to describe the condensation kinetics in the precipitated phase and the results support the negative first shell substitution effect. These findings challenge the notion of a positive first shell substitution effect in alkaline conditions.",

keywords = "Condensation kinetics, First shell substitution effect, Si MAS-NMR, St{\"o}ber particles, pH",

author = "Kangtaek Lee and Alon McCormick",

note = "Funding Information: We acknowledge the support of the National Science Foundation (CTS-89 10423) and the Center for Interfacial Engineering at the University of Minnesota. KL acknowledges the support of the Korea Research Foundation (KRF-2003-005-D00001) and Yonsei University Research Fund of 2001.",

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doi = "10.1007/s10971-005-6374-y",

language = "English",

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AU - Lee, Kangtaek

AU - McCormick, Alon

N1 - Funding Information: We acknowledge the support of the National Science Foundation (CTS-89 10423) and the Center for Interfacial Engineering at the University of Minnesota. KL acknowledges the support of the Korea Research Foundation (KRF-2003-005-D00001) and Yonsei University Research Fund of 2001.

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N2 - Using 29Si MAS-NMR we investigate the effect of pH on the final connectivity distribution of the silicon atoms in the Stöber particles. Our data suggest that the fraction of the silicon atoms that are ully-connected decreases as the ammonia concentration is increased. This suggests a more negative first shell substitution effect in the precipitated phase (liquid droplet) if condensation reactions are irreversible. A simple model is developed to describe the condensation kinetics in the precipitated phase and the results support the negative first shell substitution effect. These findings challenge the notion of a positive first shell substitution effect in alkaline conditions.

AB - Using 29Si MAS-NMR we investigate the effect of pH on the final connectivity distribution of the silicon atoms in the Stöber particles. Our data suggest that the fraction of the silicon atoms that are ully-connected decreases as the ammonia concentration is increased. This suggests a more negative first shell substitution effect in the precipitated phase (liquid droplet) if condensation reactions are irreversible. A simple model is developed to describe the condensation kinetics in the precipitated phase and the results support the negative first shell substitution effect. These findings challenge the notion of a positive first shell substitution effect in alkaline conditions.

KW - Condensation kinetics

KW - First shell substitution effect

KW - Si MAS-NMR

KW - Stöber particles

KW - pH

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Effect of pH on the final connectivity distribution of the silicon atoms in the Stöber particles

Abstract

Bibliographical note

All Science Journal Classification (ASJC) codes

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