title: Nanoscale gamma-AlO(OH) hollow spheres: synthesis and container-type functionality.
abstract: AlO(OH) hollow spheres are realized via a water-in-oil (w/o) microemulsion, applying the liquid-to-liquid-phase boundary of the micellar system as a template. Scanning electron microscopy, transmission electron microscopy (TEM), and dynamic light scattering analyses show the presence of nonagglomerated hollow spheres exhibiting an outer diameter of about 30 nm and a wall thickness of 5-6 nm. High-resolution TEM images show highly ordered lattice fringes, indicating the crystallinity of the sphere wall and identifying the wall to consist of gamma-AlO(OH) (boehmite). The container functionality of as-prepared AlO(OH) hollow spheres is validated as a proof of concept by encapsulating the fluorescent dye rhodamine (R6G) inside the alumina shell. Subsequent to centrifugation and careful purification, R6G is evidenced via photoluminescence to be still present. Finally, release of R6G is initiated by acidic dissolution of the sphere wall.
authors.affiliation: Institute of Inorganic Chemistry, University of Karlsruhe (TH), Engesserstrasse 15, D-76131 Karlsruhe, Germany.
authors.forename: Daniel H M
authors.initials: DH
authors.lastname: Buchold
authors.forename: Claus
authors.initials: C
authors.lastname: Feldmann
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry*; D003460:Crystallization; D008027:Light; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D010777:Photochemistry / Q000379:methods; D012235:Rhodamines / Q000737:chemistry; D012542:Scattering, Radiation
chemical_list: D012235:Rhodamines; C026188:rhodamine 6G; D000536:Aluminum Hydroxide