[pure-silver] Re: Cleaning picture frame glass
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 19 Apr 2006 00:28:24 -0400 (EDT)
From: "Peter Badcock" <peter.badcock@xxxxxxxxx>
Subject: [pure-silver] Re: Cleaning picture frame glass
Date: Wed, 19 Apr 2006 13:57:33 +1000
> Interesting. What physical process attracts the dust to the
> surfactant?
I don't know whether surfactant engineers have any systematic
knowledge besides empirical one. I learned a bit of surfactant
chemistry motivated by emulsion coating problems, but much of the
knowledge, besides what can be described by the molecular structure,
are empirical and heavily know-how based proprietary information in
the surfactant industry. (There are just as many surfactant compounds
in use in the industry as the number of wines you see in your local
wine distributors catalogue.)
Regarding the wetting of dust particles and glass surface, I think the
important factor is dynamic surface tension and Draves wetting
time. Like friction, surface tension can be measured in dynamic or
static context. Dynamic surface tension is larger, but I suspect
surfactants with low dynamic tension may be superior for this
application. (For wetting agents to be used by slow immersion, like
final rinse bath, these are nonissues.)
Not that this level of optimization is terribly important for glass
cleaning problem at hand, but I certainly don't want having to wipe
the glass surface any more than I have to, and after going through
this process myself, I appreciate the difference between well
formulated glass cleaners and some poorly made ones. I don't think my
glass cleaner is any more complicated than any of the good cleaners on
market, and it's certainly simpler to mix a batch in my studio without
walking over to a hardware store. (And... I use it on everything, from
negative carrier to the framing glass.)
I don't think the charge of the hydrophilic end is important. There
are some nonionic surfactants that are also good at wetting surface
very rapidly. They are just not as common as Triton X-200.
Antistatic properties are different problems. Film manufacturers
incorporate various compounds to minimize resistivity in dried films,
and they also incorporate some agents to minimize surface frictions or
surface contact area (such as silica). But in glass cleaner, where
conductivity of the solution is already very high, this sort of things
are not an issue. Detergency and degreasing properties are much more
important.
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