Super glue works like a
two-part adhesive, the glue in the tube and the hardener is water.
Most dry surfaces have microscopic droplets of water adhering to
them. When super glue comes in contact with these droplets they
create the chemical reaction that causes the super glue to harden.
You can wipe both surfaces with a very slightly damp cloth or
breathe on it, like breathing on a mirror to speed the adhesive's
setting. It sticks to skin because skin is full of large, medium,
small and microscopic grooves and pores that provide the perfect
type of roughness for glue to grab. Second, the skin tissues are
saturated with water so the super glue can soak in and find water to
cause the hardening reaction.
The super glue that doctors use is different than the type available
in hardware stores. Surgical super glue contains types of alcohols
that are less toxic to human tissue. The type sold in stores uses
ethyl of methyl alcohols that can kill cells.