Pellicle
Definition and meaning of Pellicle in chemistry.
A pellicle is a thin skin, film, or membrane that forms on the surface of a liquid, often due to oxidation, polymerization, or biological activity. In chemistry, it can also refer to a thin, semi-permeable membrane used in various separation and analytical techniques.
In more detail
Pellicles can form spontaneously when a solution interacts with air. For example, drying oils undergo cross-linking at the surface to form a tough pellicle that protects the underlying liquid. In laboratory settings, engineered pellicles are used as protective films for delicate optical components or as stationary phases in some forms of chromatography. The thickness, chemical composition, and porosity of a pellicle strongly influence its physical properties and permeability to different solvent molecules.
Key facts
| Field | Analytical Chemistry |
|---|---|
| State | Thin film or membrane |
| Formation | Surface reaction or deposition |
A thin pellicle of aluminum oxide quickly forms on the surface of exposed aluminum metal, protecting it from further corrosion.
Frequently asked questions
Are pellicles always visible?
No, some pellicles, like the initial oxide layer on certain metals, are microscopic and transparent.
Can pellicles be beneficial?
Yes, many pellicles prevent further degradation of the underlying material or serve specialized functions in instruments.