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Fluid-cell Raman Spectroscopy for operando Studies of Reaction and Transport Phenomena during Silicate Glass Corrosion
Published on: May 9, 2025
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Conduction and Excess Charge in Silicate Glass/Air Interfaces
Victor T C Paiva1, Leandra P Santos1, Douglas S da Silva1
1Institute of Chemistry , University of Campinas , Campinas 13083-970 , SP , Brazil.
Langmuir : the ACS Journal of Surfaces and Colloids
|May 25, 2019
Summary
Glass surfaces exhibit surprisingly high interfacial charge carrier mobility, behaving like ionic topological insulators. This unexpected electrical behavior is driven by mobile protons in adsorbed water layers, challenging conventional understanding of insulators.
Area of Science:
- Materials Science
- Surface Science
- Condensed Matter Physics
Background:
- Glass is a common electrical insulator, and its surface electrical properties are generally considered negligible.
- The behavior of charge carriers at the glass/air interface is not well understood, especially under varying humidity conditions.
Purpose of the Study:
- To investigate the unexpected electrical properties of the glass/air interface.
- To elucidate the mechanism behind the observed interfacial charge transport.
- To explore the potential classification of glass as an ionic analogue of a topological insulator.
Main Methods:
- Measurements of interfacial charge carrier mobility under varying relative humidity (RH).
- Surface resistance (R) measurements as a function of RH.
- Kelvin potential measurements to assess charge storage.
- Application of electric fields parallel to the surface to study RH-dependent behavior.
- Analysis of surface morphology and potential distribution changes.
Main Results:
- Interfacial charge carrier mobility was found to be exceptionally high (4.81 × 10-5 m2 s-1 V-1) at 80% RH.
- Surface resistance increased by over 5 orders of magnitude as RH decreased from 80% to 2%.
- Biased glass surfaces demonstrated charge storage capabilities.
- High RH led to excess negative charge accumulation and changes in surface morphology, including particle elimination.
Conclusions:
- The observed phenomena are explained by a protonic-charge-transfer mechanism involving mobile protons in adsorbed water layers.
- Glass surfaces exhibit characteristics of an ionic analogue of a topological insulator.
- These findings necessitate a re-evaluation of glass's electrical properties and potential applications.
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