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Structure of hydrated layers on silicate electrode glasses
1Department of Chemistry, University of Mining and Technology, Freiberg, Germany.
Solid State Nuclear Magnetic Resonance
|February 1, 1994
Summary
Hydrated silicate glasses contain two water species: silanol (SiOH) groups and hydrogen-bonded molecular water. Framework changes include formation of Q3 groups and condensation of silanol groups during swelling.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Glass Science
Background:
- Silicate glasses are crucial in various applications, including electrodes.
- Understanding water interactions within hydrated silicate glasses is key to their performance.
- Structural modifications in hydrated layers impact glass properties.
Purpose of the Study:
- To investigate structural changes in hydrated silicate electrode glasses.
- To characterize the water species and ionic content within the hydrated layer.
- To correlate structural modifications with water incorporation and swelling.
Main Methods:
- High-resolution solid-state nuclear magnetic resonance (NMR) techniques (29Si MAS, 29Si CP MAS, 1H high-speed MAS, 1H CRAMPS, 1H Echo NMR).
- Supporting techniques: Infrared (IR) spectroscopy, thermal analysis, and sodium ion concentration analyses.
Main Results:
- Identified two distinct water species: silanol (SiOH) groups and non-mobile hydrogen-bonded molecular water.
- Observed formation of Q3 groups [(SiO)3SiOH] in the hydrated glass framework.
- Found significant condensation of silanol groups during the swelling process.
Conclusions:
- Hydration of silicate glasses leads to specific structural alterations in the silicate framework.
- The presence of distinct water species influences the glass structure and properties.
- Silanol condensation is a key process during the swelling of hydrated silicate glasses.