Formation of Contaminant Droplets on Surfaces
AEROSPACE CORP EL SEGUNDO CA
Pagination or Media Count:
The effects of molecular film contamination on optical systems depend strongly on the film uniformity and thickness. Molecular films of uniform thickness are responsible for light transmission losses through absorption. For example, a partially darkened film of dioctyl phthalate 100 A thick may cause losses of about 2 in the visible spectrum. However, Ternet, et al, Villahermosa, et al, and others have shown that scattering from droplets or puddles can cause transmission losses of 30. In this report, we examine properties of the contaminant and surface that drive the formation of smooth films and droplets. It is shown that surfaces play a strong and sometimes dominant role in controlling film or droplet formation. DC 704, a high-purity, siloxane liquid, is shown to assume both droplet and smooth film character depending on the surface.
- Physical Chemistry
- Fluid Mechanics