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Nanoscale gamma-AlO(OH) hollow spheres: synthesis and container-type functionality
Daniel H M Buchold1, Claus Feldmann
1Institute of Inorganic Chemistry, University of Karlsruhe (TH), Engesserstrasse 15, D-76131 Karlsruhe, Germany.
Nano Letters
|October 26, 2007
Summary
We synthesized novel aluminum oxyhydroxide (AlO(OH)) hollow spheres using a microemulsion method. These crystalline nanospheres demonstrate potential as containers for fluorescent dyes, with controlled release capabilities.
Area of Science:
- Materials Science
- Nanotechnology
- Colloid Chemistry
Background:
- Microemulsion techniques offer versatile templating for nanomaterial synthesis.
- Hollow nanostructures provide unique properties for encapsulation and controlled release applications.
Purpose of the Study:
- To synthesize and characterize AlO(OH) hollow spheres using a water-in-oil microemulsion.
- To evaluate the container functionality and controlled release of encapsulated substances from these spheres.
Main Methods:
- Water-in-oil (w/o) microemulsion as a template for hollow sphere formation.
- Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) for characterization.
- Photoluminescence spectroscopy to confirm dye encapsulation and release.
Main Results:
- Successfully synthesized nonagglomerated AlO(OH) hollow spheres with 30 nm outer diameter and 5-6 nm wall thickness.
- TEM analysis confirmed crystalline gamma-AlO(OH) (boehmite) wall structure with ordered lattice fringes.
- Demonstrated encapsulation of rhodamine (R6G) dye within the spheres, with evidence of release upon acidic treatment.
Conclusions:
- AlO(OH) hollow spheres can be effectively synthesized using microemulsion templating.
- The synthesized spheres exhibit excellent container functionality for fluorescent dyes.
- Controlled release of encapsulated materials is achievable through pH-triggered dissolution of the sphere wall.
