Talk:Contact angle

message: In the last diagram of the page, a mysterious tensoin arrow is labeled as "SG", I believe this is supposed to be SV. Someone fix it!
Wouldn't it also be nice if the tension arrows were scaled according to the Young Equation?
It would be good to show an example on this page of both a -phobic and -philic contact angle.204.227.241.18 22:14, 15 August 2007 (UTC)
thread_title: Edit Picture Needed

message: How can you have a contact angle greater than 90? Does anyone have a picture of this?--UltraHighVacuum 20:56, 12 December 2006 (UTC)
replies: text: This is answered in the text 'typical contact angles', with pictures if you follow links. —The preceding unsigned comment was added by Berland (talk • contribs) 09:27, 17 January 2007 (UTC)
thread_title: 150 degrees?

message: It sounds like materials have a characteristic contact angle with water, eg gold 77° copper 85° silicon 32°.  Is there a place we can get all this data for many substances so that we can have a table of angles? Graeme Bartlett (talk) 23:16, 23 January 2012 (UTC)
thread_title: Table of angles

message: The discussion below is about the possibility of adding a description of another technique to evaluate the equilibrium contact angle, namely vibration technique. The problem, as it appears from the rather long discussion below, is that there is no agreement as to which vibration method is correct (vibration amplitude, frequency, direction etc. were not yet agreed upon in the literature so which one should be used in the wiki file?). While the Tadmor equation is currently the more frequently used one in the literature, vibration techniques appeared historically at an earlier stage, which can add another dimension to their description.
: Can anyone add a description of vibration experiments to obtain the equilibrium contact angle? I think it can be a good addition to the Tadmor equation which is currently the only way  — Preceding unsigned 06:40, 12 September 2012 (UTC)
replies: text: In fact the Tadmor equation appears or used in more that 60 papers (not just cited) including papers by Israelachvili (see: LANGMUIR  Volume: 28   Issue: 41   Pages: 14609-14617). It was cited even more times, which is remarkable in view of the short time period since it was introduced. Anyway, see reply below.  —
Reply: Sure, just go ahead and add a description of vibration techniques, I am willing to go over it and if needed refine it. Note though that the equilibrium contact angle is not a measurable parameter - you will always get a contact angle hysteresis and the value of the equilibrium contact angle will be somewhere between the advancing and receding contact angles. Its location within this spectrum can only be found out from the Tadmor equation.
There is a paper (I think it is by dela Volpe but not sure, I wonder if you can find it, because I must have misplaced it somehow) that describes how one can vibrate a surface and reach an equilibrium contact angle. I love this paper and I think it should be addressed as well here. The readers of this wiki article are not aware of the subtlety between the "as placed" contact angle and the Young contact angle, and adding the explanation of the surface vibration technique can add merit to the article. While I believe that the equilibrium reached with the vibration technique is the Young contact angle, I never saw a thermodynamic proof for it. On the other hand there is such a proof with the Tadmor equation. The reason I believe that the vibration technique does provide the Young equilibrium is that I checked once, and it resulted in values which were very close to the values obtained with the Tadmor equation. Anyway, thank you for discussing this with me, let's try to resolve this issue.
Reply: Surfaces have been created with no measurable hysteresis (e.g. by Zisman).  The use of vibration to reach Young's angle has been described in several papers (Andrieu et al., Decker & Garoff, della Volpe et al. as you say, and others).  It can be understood in terms of overcoming energy barriers which is a concept that goes back to Shuttleworth & Bailey and through a line of prominent papers since then such as Bikerman, Good, Johnson & Dettre, Neumann & Good, etc.  I would consider this to be the widely accepted way of thinking about hysteresis, which should appear in this article. Roccas1 (talk) 17:03, 19 August 2012 (UTC)
thread_title: Should vibration methods be mentioned to complement the Tadmor equation approach

message: Advantages and disadvantages 157.47.24.232 (talk) 15:48, 24 February 2024 (UTC)
thread_title:  Physics