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Synthesis and Characterization of Supramolecular Colloids
Published on: April 22, 2016
Surface modification for stability of nano-sized silica colloids
Khoa N Pham1, Damian Fullston, Kwesi Sagoe-Crentsil
1CSIRO Manufacturing and Materials Technology, CSIRO, Graham Road, Highett, Victoria 3190, Australia. khoa.pham@csiro.au
Journal of Colloid and Interface Science
|August 10, 2007
Summary
Surface modification of nano-sized silica particles prevents aggregation in nonaqueous solvents. Aminosilane treatment yields extremely stable colloidal silica, maintaining physical and electrochemical properties.
Area of Science:
- Materials Science
- Colloid Chemistry
- Surface Chemistry
Background:
- Commercial 30-nm colloidal silica particles possess high surface area and reactivity.
- Small particle size increases susceptibility to irreversible aggregation during surface modification.
- Previous studies with larger particles did not encounter similar aggregation issues.
Purpose of the Study:
- To compare surface charge results under various reaction conditions and characterization methods.
- To investigate the mechanism of instability in nano-sized silica suspensions.
- To develop stable nano-sized silica particles for nonaqueous applications.
Main Methods:
- Surface modification of silica particles using functional silanes.
- Zeta potential measurements as a function of pH.
- Gelation kinetics analysis.
- Refluxing of silica particles in a nonaqueous solvent.
- Aminosilane surface modification.
Main Results:
- Refluxing in a nonaqueous solvent stabilized silica particles, preserving size and electrochemical behavior.
- Aminosilane surface modification resulted in extremely stable particles.
- Identified factors contributing to aggregation, including nonaqueous solvents and high trialkoxysilane concentrations.
- Highlighted the role of reactive silanol groups in particle instability.
Conclusions:
- Surface modification strategies can effectively prevent aggregation in nano-sized silica.
- Aminosilane treatment is a highly effective method for achieving stable colloidal silica suspensions.
- Understanding surface chemistry and reaction conditions is crucial for controlling nanoparticle stability.
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