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Q & A: Why skin flakes stick to the wall?

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Most recent answer: 07/18/2015
Q:
20 year old son has very bad eczema. As a result, dead skin is constantly falling off through scratching. He therefore daily sweeps the skin off his bed, which you would think would just land on the floor. Interestingly, i see that it sticks to the wall. At first I thought the wall had pieces of lint from a hoodie. But it's the dead, greasy dead skin that sticks to the wall. Could this possibly be from an elecromagenetic field in the room from cell phone, computer, t.v. and beat machine, which are plugged in all night? Any other thoughts?
- carol (age 62)
new york
A:

I think the issue is more related to static electricity, rather than EM waves from some home appliance, which are expected to be quite weak. Your observation seems to be resemble a hair sticking to a baloon, if it is rubbed against a suitable surface. And my observation is that hair also sticks to the surfaces like walls, which is typically painted. The wall paints are similar to the content of a baloon: it is basically an organic polymer mixture, acrylates, urethane...

Both epidermal skin, hair and nails are heavily made of keratin proteins, the difference between their physical properties mostly are due to the sulphur content. Keratin has a pKa ~4.5, meaning it has a tendency to acquire negative charges in neutral solutions. But charging can also be easily induced by mechanical effects (a.k.a triboelectric effect).  I think the sweeping of the flakes from the bed (as well as soles of your slippers) introduces charges this way. Since keratin is a good insulator, it will be retained on the specimen for a while. This will then induce charge/dipole reorganisation on the target surface making them stick initially, followed by other bond establishments (H-bonds).

Tunc


(published on 07/18/2015)

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