I have a suspension of diamond nano-powder (let's say, though it works for many
types of powders) in distilled water (deionized or not). This is put on a
typical glass microscope slide, and allowed to dry under normal conditions.
After drying (I suspect even this definition could get argued about), the powder
is stuck to the slide, until mechanically dislodged. Once dislodged, the powder
is no longer "stuck" to the slide, at least for most macroscopic disturbances.
Why?
Does the water get much of the powder "close enough" -- to the slide, and to
neighboring grains -- to allow shorter-range forces to come into play?
Is there enough of the glass (or powder) material dissolved to serve as a
glue matrix?
Is there enough air absorbed to serve as a glue matrix?
Upon "drying", is there a significant amount of water left behind to serve as
a mono-layer glue?
/**************************************
As a species, we are forever sticking our fingers into the electric socket of
the Universe to see what'll happen next. It's a trait that'll either save us or
kill us, but by god it's what makes us human beings. I'd rather be in the
company of people who look at Mars than people who contemplate humanity's navel
-- other worlds are better than fluff. ~~Sir Terence David John Pratchett
***************************************/