Stable colloids in molten inorganic salts
A colloidal solution is a homogeneous dispersion of particles or droplets of one phase (solute) in a second, typically liquid, phase (solvent). Colloids are ubiquitous in biological, chemical and technological processes1, 2, homogenizing highly dissimilar constituents. To stabilize a colloidal system against coalescence and aggregation, the surface of each solute particle is engineered to impose repulsive forces strong enough to overpower van der Waals attraction and keep the particles separated from each other2. Electrostatic stabilization3, 4 of charged solutes works well in solvents with high dielectric constants, such as water (dielectric constant of 80). In contrast, colloidal stabilization in solvents with low polarity, such as hexane (dielectric constant of about 2), can be achieved by decorating the surface of each particle of the solute with molecules (surfactants) containing flexible, brush-like chains2, 5. Here we report a class of colloidal systems in which solute particles (including metals, semiconductors and magnetic materials) form stable colloids in various molten inorganic salts. The stability of such colloids cannot be explained by traditional electrostatic and steric mechanisms. Screening of many solute–solvent combinations shows that colloidal stability can be traced to the strength of chemical bonding at the solute–solvent interface. Theoretical analysis and molecular dynamics modelling suggest that a layer of surface-bound solvent ions produces long-ranged charge-density oscillations in the molten salt around solute particles, preventing their aggregation. Colloids composed of inorganic particles in inorganic melts offer opportunities for introducing colloidal techniques to solid-state science and engineering applications.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- Office of Naval Research; National Science Foundation (NSF); National Institutes of Health (NIH); USDOE Office of Science
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1389810
- Journal Information:
- Nature (London), Journal Name: Nature (London) Journal Issue: 7641 Vol. 542; ISSN 0028-0836
- Publisher:
- Nature Publishing Group
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nanocrystals in Molten Salts and Ionic Liquids: Experimental Observation of Ionic Correlations Extending beyond the Debye Length
Method for the preparation of metal colloids in inverse micelles and product preferred by the method
Restabilization of electrosterically stabilized colloids in high salt media
Journal Article
·
Mon Apr 08 20:00:00 EDT 2019
· ACS Nano
·
OSTI ID:1558110
Method for the preparation of metal colloids in inverse micelles and product preferred by the method
Patent
·
Tue Dec 31 23:00:00 EST 1991
·
OSTI ID:868468
Restabilization of electrosterically stabilized colloids in high salt media
Journal Article
·
Thu Nov 30 23:00:00 EST 2000
· Langmuir
·
OSTI ID:15001101