Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] Prising electrons from the atom



Triboelectricity is a tricky topic. As John says, rubbing one metal against another doesn't do it. It will serve to remove the surface films so that the metals are indeed in direct contact, and then electron transfer can occur depending on the work functions.

Triboelecticity seems to occur most often when one of the materials is a polymer. Sherwood and Chabay do a nice job of showing that the energies involved are not sufficient to transfer electrons, but could transfer charged polymer fragments.

So I don't think triboelectricity is the way to think about this. Isn't the problem a matter of how to affectively couple to the electrons...a hammer just doesn't do it.

joe
Joseph J. Bellina, Jr. Ph.D.
Professor of Physics
Saint Mary's College
Notre Dame, IN 46556

On Dec 18, 2008, at 2:17 AM, John Denker wrote:

In the context of triboelectricity ...

On 12/17/2008 11:27 PM, Bernard Cleyet wrote:
I don't think it's adhesion, just differences in Fermi levels.

Agreed.

A cube of gold will adhere to another cube of gold, rather
dramatically in fact.

In contrast, if you want to create static electricity,
rubbing gold on gold is not a good strategy. It would
work better with two /different/ substances.

For lots more details on this, see
http://www.av8n.com/physics/contact-electrification.htm


================

Slight nitpick: I would have preferred to say differences
in _work functions_ rather than "Fermi levels" in this
situation. Of course the physics of work functions is
intimately tied to the physics of Fermi levels ... but
there's other stuff going on, too, and the zero-reference
for the work function is defined in more-or-less exactly
the right way for this application. The zero of the Fermi
levels is not so immediately relevant.

_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l