Lyophobic
Definition and meaning of Lyophobic in chemistry.
Lyophobic refers to a substance or a colloidal dispersion that inherently lacks an affinity for the surrounding dispersing liquid medium.
In more detail
The term translates roughly to "solvent-hating" in Greek. In a lyophobic colloid, there is very little chemical or physical interaction between the dispersed phase and the continuous phase. Because of this distinct lack of affinity, lyophobic sols are thermodynamically unstable and tend to coagulate or precipitate very easily if even a small amount of an electrolyte is added, or if the mixture is subjected to heating or shaking. They are typically prepared using special mechanical dispersion or chemical condensation methods, since they do not form spontaneously simply by mixing the substance with the solvent.
Key facts
| Field | Physical Chemistry |
|---|---|
| Meaning | Solvent-hating |
| Stability | Thermodynamically unstable |
A dispersion of metallic gold nanoparticles in water is a classic lyophobic sol, as the gold has no natural affinity for the polar water molecules and requires a specialized stabilizing capping agent to prevent irreversible coagulation.
Frequently asked questions
What is the difference between lyophobic and hydrophobic?
Lyophobic is a broad, general term meaning solvent-hating for any given liquid medium, whereas hydrophobic specifically refers to a lack of affinity when the solvent is water.
How can a lyophobic sol be stabilized?
They are often stabilized by adding a protective lyophilic colloid or by ensuring the particles carry the same electrical charge, causing electrostatic repulsion.