Permeable Silica Shell through Surface-Protected Etching
- 12 August 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 8 (9), 2867-2871
- https://doi.org/10.1021/nl8016187
Abstract
We describe a “surface-protected etching” strategy that allows convenient conversion of sol−gel derived silica into porous structures. Poly(vinyl pyrrolidone) is used to protect the near surface layer, and NaOH is used to selectively etch the interior of the silica spheres. Etching initially yields porous structures and eventually removes the core to leave behind hollow silica spheres with porous shells. This strategy is useful for constructing core−shell systems where active nanomaterials are embedded in silica shell for enhanced stability against aggregation. We experimentally demonstrate use of the surface-protected etching approach to create openings on silica shells; these openings allow dissolved chemical species to reach embedded catalytic particles to be chemically transformed while the porous shells continue to act as effective barriers against aggregation and loss of activity of the core particles. We also show that, by controlling the extent of etching, it is possible to control the permeation rate of the chemical species through the shells.This publication has 20 references indexed in Scilit:
- Successive interaction of pairs of soluble organics with nanosilica in aqueous mediaJournal of Colloid and Interface Science, 2006
- NMR Solvent Relaxation in Studies of Multicomponent Polymer AdsorptionLangmuir, 2002
- Modifying the Surface Properties of Superparamagnetic Iron Oxide Nanoparticles through A Sol−Gel ApproachNano Letters, 2002
- Synthesis of Nanosized Gold−Silica Core−Shell ParticlesLangmuir, 1996
- Organic-inorganic polymers hybridsPublished by Walter de Gruyter GmbH ,1995
- Isotropic and Birefringent Dispersions of Surface Modified Silica Rods with a Boehmite-Needle CoreLangmuir, 1994
- Preparation and properties of uniform coated colloidal particles. VII. Silica on hematiteJournal of Colloid and Interface Science, 1992
- The sol-gel processChemical Reviews, 1990
- Adsorption of poly(vinyl pyrrolidone) on silica. II. The fraction of bound segments, measured by a variety of techniquesJournal of Colloid and Interface Science, 1982
- The adsorption of poly(vinyl pyrrolidone) onto silica. I. Adsorbed amountJournal of Colloid and Interface Science, 1982