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A Synthetic Methodology for Preparing Impregnated and Grafted Amine-Based Silica Composites for Carbon Capture
Published on: September 29, 2023
Attractive double-layer forces and charge regulation upon interaction between electrografted amine layers and silica
Gunnar Dunér1, Joseph Iruthayaraj, Kim Daasbjerg
1KTH Royal Institute of Technology, School of Chemical Sciences and Engineering, Department of Chemistry, Surface and Corrosion Science, Stockholm, Sweden. gduner@kth.se
Journal of Colloid and Interface Science
|July 31, 2012
Summary
Amine functionalities were electrografted onto glassy carbon surfaces. The resulting layers exhibit swelling in water and significant charge regulation, influenced by counterion incorporation.
Area of Science:
- Surface Chemistry
- Materials Science
- Nanotechnology
Background:
- Glassy carbon surfaces are widely used in electrochemical applications.
- Functionalization of surfaces is crucial for tailoring material properties.
- Electrografting offers a versatile method for surface modification.
Purpose of the Study:
- To introduce amine functionalities onto glassy carbon surfaces via electrografting.
- To characterize the structural and mechanical properties of the grafted layers.
- To investigate the interfacial forces between aminated surfaces and silica particles in aqueous solutions.
Main Methods:
- Electrografting of 4-(2-aminoethyl)benzenediazonium tetrafluoroborate.
- Ellipsometry for layer thickness determination.
- Atomic force microscopy (AFM) PeakForce QNM for nanomechanical mapping.
- Force measurements between aminated glassy carbon and silica particles at varying ionic strength and pH.
Main Results:
- A 2.5 nm thick, low-roughness amine-functionalized layer was successfully grafted.
- The layer exhibited swelling in aqueous solutions and topographical clustering.
- Attractive double-layer forces dominated interactions between surfaces at large separations.
- Significant charge regulation was observed, with surface charge density increasing upon decreasing separation.
Conclusions:
- Electrografted amine layers on glassy carbon show tunable properties in aqueous environments.
- Interfacial forces are governed by electrostatic interactions and influenced by ionic strength and pH.
- Counterion incorporation within the water-rich grafted layer contributes to the observed low surface charge density and significant charge regulation.
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