Talk:Contact electrification

Merge
I started adding some info about contact electrification in general to triboelectric effect. I now see that triboelectric specifically refers to different materials, so I will remove that info. I think maybe the two articles should be merged, however. I see that neither article seems to be aware of the other. - Omegatron 19:10, August 7, 2005 (UTC)


 * It seems to me there's a huge amount of history that could be added to Triboelectric effect, and also all the other phenomena mentioned here, so I've removed the merge tags. I'll try to bring more attention to them from historians of science. -- Beland 01:51, 13 August 2005 (UTC)


 * This article covers topics which were once erroneously thought to be related but are now clearly seen as unrelated, and are covered elsewhere: triboelectric effect, Volta potential, semiconductor Fermi levels. This should be made clearer in the lead para.  It should stick close to the history and not recap the scientific topics.  -- Chetvorno TALK 17:39, 7 September 2008 (UTC)

The effect is most pronounced with two dissimilar materials, but it can happen with, say, two identical objects at different temperatures as well.

(somebody's unsigned comment above) I find the sentence "An important fact leading to the rejection of the theory of contact tension was the observation that corrosion, that is, the chemical degradation of the battery, seemed unavoidable with its use, and that the more electricity was drawn from the battery, the faster the corrosion proceeded" quite confusing.

The "it" in "with its use": refers to the battery, right, not to corrosion? What is being said here? In what sense is the word "seemed" being used in "seemed unavoidable"? Seemed according to actual real-life experience with batteries? (If so, what's "seemed" about it? Isn't corrosion of batteries a fact, even now) Or is this "seemed" referring to some apparent conclusion of the now-discredited theory?

The relevance of "and that the more electricity was drawn from the battery, the faster the corrosion proceeded" is also not clear to me.

I am just guessing here, but I think the writer intended to say something like: real life batteries corrode with use, and there is nothing in the "contact electrification" model of how things acquire electric charge to explain this. (From the page, I'm not sure if there is anything about contact electrification that is at all _at odds with_ or _contradictory_ to the fact that batteries corrode, but the fact that the model of electrification sheds no light on why this real life fact happens is understandably a weakness of the model.) If something more complicated than this was meant, somebody familiar with the relevant details should supply it. It is missing.

In my opinion this page should explain what contact electrification is in the first sentence. The current edition tells us in the first sentence that it is an obselete scientific theory. Then we get a somewhat abstracted, non-focused narrative of the various electrical phenomena people observed in the 18th century. Then we get a discussion of something called "contact tension", which I am guessing is another name for contact electrification and not some different concept. The definition of contact electrification should come first. Then and only then should we be told why it is obsolete (not, apparently, because it is "discredited" in any fundamental way, but because it does not distinguish between ways of producing electric charge differences that we now recognize are entirely different from one another). 75.167.202.118 (talk) 21:33, 31 May 2009 (UTC)

Contact electrification vs. Triboelectric Effect
I seriously think this article is quite flawed and gives a completely wrong impression, what contact electrification actually is. The german version is much better. First I absolutely do not agree in the statement that contact electrification is an "obsolete theory". This statement is argued by the paper indicated. But if one actually reads this paper, it is obvious that the paper does only state that the early contact electricity theory as stated by the early scientist is wrong, not the current explanations. There are many papers today, where this "obsolete" effect is studied, and they all call it even nowadays "contact electrification". Sure there are some quite different effects involved (which should be described in here), but nontheless, in practise, mostly they go by the name "contact electrification" even today. I think the explanations, as given by the german Wiki would be much better. Namely that contact electrification has several reason (of which some are still being researched today). And especially that the "Triboelectric effect" is and should be actually called obsolete, for it doesn't exist! The Triboelectric effect is just a mix of different clearly distuingishable other effects, like contact electrification, piezo electricity, fracto electricity, ... 83.76.230.5 (talk) 09:38, 11 July 2011 (UTC)
 * You have a good point, but since contact electrification is already several effects, and you say the triboelectric effect is explained by contact electrification or other effects, what is the meaning of triboelectric as distinguished from contact identification? 84.227.226.188 (talk) 11:35, 12 April 2014 (UTC)
 * Indeed "contact electrification" is a scientifically valid term in use today. See https://science.sciencemag.org/content/333/6040/308.abstract I've tagged the article as disputed as it should be rewritten by someone who knows what they're talking about. 31.10.165.54 (talk) 07:57, 27 April 2020 (UTC)
 * Here's another more recent paper that uses the term. . The claim that "Contact electrification was an erroneous scientific theory" is false. The source cited in support of the claim that it is an obsolete theory does not even contain the phrase "contact electrification", so I'm removing the claim and citation and I'll attempt to rewrite it. But I really don't know enough about this to do it justice, so if someone who actually understands this could look it over, that would be appreciated.  Sparkie82 ( t • c ) 16:53, 3 November 2021 (UTC)
 * I agree with the above comments. This article confuses two topics:
 * Effects due to work function differences in metals or semiconductor junctions.
 * Electrochemical effects in batteries and similar.
 * I suggest removing the electrochemical parts. Use the more conventional definition, see https://doi.org/10.1080/00018738000101466
 * When I find time I can have a go at this, trying to be fair to conflicting views (there are many). I will also add some missing but important information such as charging of powders which belongs here. Ldm1954 (talk)

16:32, 28 February 2023 (UTC)

Metallic contact voltage difference?
From the section entitled Metallic Contact: The process is halted when the difference in electric potential (electrostatic potential) between the two metals reaches a particular value, namely the difference in work function values - usually less than one volt. At this point, the Fermi levels for the two metals are equal, and there is no voltage difference between them.

Is a voltage difference the same as a potential difference? If so, this explanation makes no sense, since it says that there is and is not a potential difference. 84.227.226.188 (talk) 13:10, 12 April 2014 (UTC)

Merge Triboelectric effect into this article?
I would like to propose to merge the Triboelectric Effect (TE) article and the Contact Electrification (CE) article. TE is a type of CE that involves "rubbing" (hence tribo-). While the two can be distinguished this way, the overlap between the two are simply too great to merit separate articles. The solution is to have the main article be Contact Electrification (TE redirecting to CE) with a sentence explaining that TE is a type of CE. Much of the current content in the CE page is questionable, and both pages (TE and CE) needs some serious fact checking and citations. There also seems to be confusion in discerning TE/CE versus static electricity versus various types of electrical discharges. TE/CE is about the buildup of electrical charge, static electricity is the interaction of static (immobile, or at least confined to a bounded substance) charges with its surroundings, and there are various types of electrical discharges (due to mobile charges) as well. Only information about the buildup of electrical charge belongs here - other information can be linked for further reading. And finally, while the history of these subjects are certainly interesting, there is already a rather comprehensive article about the History of electromagnetic theory which can also be linked. I would like to undertake this task in a few days, but I first want to engage others watching this article.--Acolaos (talk) 02:48, 20 December 2018 (UTC)


 * Oppose - It seems to me that there is enough content in both subjects to merit continuing to have separate articles. This article is essentially a historical article.  CE is a now-discredited historical theory of the generation of electric charge that lumped together what we now know are separate, unrelated mechanisms for charge separation: the triboelectric effect (in insulators), electrochemical cell (in the Voltaic pile), and work function (in metal-metal contacts).  Even if the term "contact electrification" is still used some in modern physics, it doesn't have its previous meaning.   In contrast, the TE is a well established surface physics effect which, in addition to historical uses, has many modern applications.  It seems to me unreasonable and misleading to direct readers to an article about a false historical theory for information on a true modern theory. --ChetvornoTALK 01:31, 21 December 2018 (UTC)
 * Reply - Thank you for the reply! • I believe that contact electrification (CE) is not a discredited historical theory. A look at Willem Hackmann's The Enigma of Volta's "Contact Tension" and the Development of the "Dry Pile" that is referenced in the CE article actually never mentions CE, but instead "contact tension." I have not checked if Volta himself ever wrote "contact electrification" in his theories and this is worth taking another look. In contrast, modern research on CE and the triboelectric effect (TE) often references CE directly (DOI: 10.1126/science.1201512, doi:10.1088/0022-3727/44/45/453001). • The combination of calling CE a discredited theory and including valid mechanisms of CE (Sections 2-5) is strange to me. • My main argument for the merger is that CE is the overarching study of how things transfer charge on contact and TE is a subset of CE. — Preceding unsigned comment added by Acolaos (talk • contribs) 15:55, 21 December 2018 (UTC)
 * Could you clarify whether you are proposing merging Triboelectric effect into Contact electrification or Contact electrification into Triboelectric effect? Your text says the former, but your merger tag at the top of the page says the latter. Could you change one or the other to make the page consistent so editors won't be confused about what is being proposed? Thanks! --ChetvornoTALK 18:12, 21 December 2018 (UTC)
 * Sorry about that - I am still learning a lot about the rules here. I've updated the merger tag. --Acolaos (talk) 19:41, 21 December 2018 (UTC)

Contact electrification and Triboelectricity confused
Please see comment I have added to talk in Triboelectricity page. These are confused because the science is not settled. Ldm1954 (talk) 15:59, 28 February 2023 (UTC)


 * This article was a hopeless confusion of electrochemistry and some contact electrification. I removed what was wrong, and will add to the triboelectricity page as it should all be one topic. Later turn this into a redirect. Ldm1954 (talk) 13:11, 16 June 2023 (UTC)

New layout
I will suggest the below, then wait a week or two before doing anything.

Contact electrification is a phrase that describes the phenomenon whereby two surfaces become electrically charged when they contact and then separate. It can be a boon or a bane in industries  ranging from xerography to packing of pharmaceutical powders, and plays a critical role in many processes such as dust storms and planetary formation.

While many aspects of contact electrification are now understood, and consequences have been extensively documented, their remain disagreements in the current literature about the underlying mechanisms. Indeed, whether it is different from triboelectricity is not clear. As mentioned above contact electrification is when two bodies contact then separate; triboelectricity includes sliding. Very early it was suggested by Volta and Helmholtz (see ) that the role of sliding was to produce more contacts per second, so the two are the same. The idea here is that electrons move many times faster than atoms, so the electrons are always in equilibrium when atoms move, what is called the Born–Oppenheimer approximation. Then again, a recent paper has suggested that the sliding can act as a pump which can excite electrons to go from one material to another, and another has suggested that local heating during sliding matters. Other papers have considered that local bending at the nanoscale dominates. The jury is still out.

This article will focus on the transfer of charge when two materials contact each other and then separate, leaving aside sliding.