How do adhesives (i.e superglue) not stick to their container?
Asked by: Sarah Abel
Answer
Superglue is based upon a cyano-acrylate monomer which requires moisture, usually in the
form of water or some other active hydrogen bearing compound to polymerise. Superglue will
not stick to the tube as the inside contains oxygen, in the form of air, but excludes
water. Thus oxygen inhibits the process of polymerisation while water catalyses the
reaction.
This explains why a thin layer of glue is ideal to bond two surfaces together rather than a
thick layer of glue. A thin layer can easily obtain the moisture it needs to catalyse from
the atmosphere, while a thick layer is unable to do so.
This also explains why spilt glue adheres so well to your skin; skin being warm and moist
makes an ideal substrate.
Answered by: David Latchman, B.Sc. Physics, University of the West Indies
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '