6, increasing the concentration of surfactant was found to desorb
When the pumpdown enters the drydown zone, the water molecules will slowly desorb
and some of them will be pumped away.
Outgassing is defined as a combination of the desorption of surface adsorbed gas and gas from the bulk of the material that diffuses to the surfaces, adsorbs, and then desorbs
For example, if Al had been chosen, you'd have to make sure the surface hadn't been anodized since the oxide film absorbs large quantities of water vapor and then slowly desorbs
them into the vacuum space.
If a fresh O-ring is used on a system, the Viton will act as a source of water vapor during use until it's been under vacuum for weeks or months as the water diffuses from the O-ring's vacuum-exposed surface and desorbs
As with internal surface sources, the desorption rate decreases with time as the original heavy coverage desorbs, but the water vapor molecule population on the surface is replaced by water molecules diffusing from within the O-rings' bulk.
The layers closest to the chamber's surface will be more strongly bound and will desorb more slowly since desorption only occurs when the water molecule has absorbed enough energy to overcome the energy binding it to either the surface or the next water molecule.
The first is outgassing, which is composed of gas--usually water vapor--desorbing from the vacuum-side surfaces and diffusion transport from the bulk to the same surface where it also desorbs
If one part of the system is hotter or colder than the rest, the system will behave like a still, in which water desorbs
from the hotter part and resorbs on the colder part.
Many food packaging materials used by the refrigerated food industry are hygroscopic and adsorb or desorb
water depending on the conditions they experience as they pass through the cold chain.