precipitation from colloid solutions
(rus. осаждение из коллоидных растворов)
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a technique for producing isolated nanoparticles and nanopowders that implies interruption of chemical reaction between solution components, e.g., by way of abrupt pH increase, at a certain moment in time, after which the system's liquid colloid state changes to a disperse solid state.
Description
Precipitation from colloid solutions enables the production of stabilised nanoparticles with a very narrow size distribution, as well as core-shell particles (e.g., CdSe/ZnS, HgS/CdS or TiO2/SnO2).
The major challenge in precipitation from colloid solutions is the need to avoid aggregation of produced nanoparticles. Stabilisation of colloid particles and clusters is achieved by the use of ligands represented by different polymers and surfactants.
This technique is used, for example, to produce nanopowders of metal sulphides in a reaction of hydrosulphuric acid H2S with a water-soluble metal salt.
The major challenge in precipitation from colloid solutions is the need to avoid aggregation of produced nanoparticles. Stabilisation of colloid particles and clusters is achieved by the use of ligands represented by different polymers and surfactants.
This technique is used, for example, to produce nanopowders of metal sulphides in a reaction of hydrosulphuric acid H2S with a water-soluble metal salt.
Author
- Gusev Alexander I.
Sources
- Gusev A. I. Nanomaterials, Nanostructures, and Nanotechnologies (in Russian) // Fizmatlit, Moscow (2007) - 416 pp.
- Kozhevnikova N.S. Rempel A.A.Physical Chemistry of Aqueous Solutions: Theoretical Fundamentals and Synthesis of Promising Semiconducting Optical Materials. (in Russian) - Ekaterinburg: UPI, 2006. - 148 pp.