On Sun, 17 Sep 2017 22:42:35 +0100,
Mike Coon wrote:

Buit I thought that every atom has an "outer layer" of electrons. (Well
maybe hydrogen's single electron is a degenerate "layer"!)

But I agree if "ionic" means electrostatic (like Na and Cl in salt) it
seems unlikely...

Mike.

Hi Mike,
I thank you for your opinion where I realize the extreme hazards of
responding on something that, most likely, none of us actually know the
answer to (least of all me).

Like you, I can't imagine that ionic bonding is going on here, although I
will readily admit I only have the chemistry training that everyone has,
which is, for ionic bonding, classically portrayed by the metal sodium and
the non-metal chlorine.

This bonding is an electrostatic force between oppositely charged ions,
anions and cations if you will, where the requirement is that both
compounds be ionic.

Taking our three common household glues:
1. Elmers (paper to wood)
2. Crazy (plastic to plastic)
3. Goop (rubber to leather)

I can't imagine that any of those materials are ionic, whether they be
paper, wood, plastic, rubber, or leather.

Can you?

If it's not ionic (which I can't imagine that it is), then we have covalent
bonding, which is a more complex sharing of electrons between atoms.

How is covalent bonding going on with plastic to plastic cyanacrylate
(crazy glue, Eastman Kodak 910) stuff?

The whole purpose of sharing electrons is to become more stable where, in
the case of glueing two things together, stability isn't what's happening.

For example, when I glue rubber to leather, stability of either the rubber
or the leather isn't the issue for the molecules. And yet, they're stuck
together so "some" kind of force must exist.

But what is that force of glue?

Clearly there "is" a bonding force.
But what is that bonding force?