Mercury adhesion and wetting to plastics/polycarbonate/glass

In summary, the speaker is working on a project involving a small MHD system and wants to use clear plastic for test purposes. They are concerned about surface adhesion and friction with the mercury, and ask if polycarbonate glass and copper are suitable materials. The speaker also mentions the possibility of using palladium or platinum for the electrodes.
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Hi, I am starting to make some experiments with my project and part of it involves developing a small MHD system. Now for test purposes and ease of manufacturing I have decided I want to use some clear see through plastic which would help me see whether my experiment is working as planned. My question is since I am making a loop in which mercury will travel under MHD flow, I obviously need as low surface adhesion/friction as possible. I know that mercury has a very low adhesion to most surfaces naturally, my question is does mercury "live well" with polycarbonate glass and will it not wet the glass surface as I need the mercury to not attach to the walls and slow down.?

I will also need to insert electrodes into my system , is copper ok with mercury or does ti react with it? All in all I need my materials such that the mercury doesn't wet itself to the walls and at the same time that I have electrodes with which the mercury has good contact,

Any suggestions are appreciated, thanks.
 
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  • #2
Mercury will form an amalgam with copper.
 
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I guess I will need to coat the copper electrodes with some other metal right ?

The only metals that have high conductivity and are compatible with mercury seem to be the pgm group like palladium or platinum, I wonder how complicated it would be to electroplate one of these on a thin copper sheet.
 
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1. How does mercury adhere to plastics?

Mercury adheres to plastics through a process called wetting, which involves the spreading of the liquid metal over the surface of the plastic. This is due to the difference in surface energies between mercury and plastics, causing the mercury to spread out and form a thin layer on the plastic surface.

2. What factors affect mercury adhesion to plastics?

The surface energy and surface roughness of the plastic, as well as the temperature and purity of the mercury, can all affect the adhesion of mercury to plastics. The type of plastic also plays a significant role, with some plastics being more compatible with mercury than others.

3. Can mercury adhere to polycarbonate?

Yes, mercury can adhere to polycarbonate plastic. However, polycarbonate has a higher surface energy compared to other plastics, which can make it more difficult for mercury to wet and adhere to its surface. Pre-treatment of the polycarbonate surface with chemicals or plasma can improve adhesion.

4. How does mercury adhere to glass?

Mercury has a strong adhesion to glass due to the low surface energy of glass. This allows the mercury to easily wet and spread over the glass surface. However, the adhesion can be affected by the presence of contaminants on the glass surface, which can reduce the surface energy and hinder the wetting process.

5. What applications require good mercury adhesion to plastics and glass?

Mercury adhesion to plastics and glass is important in various applications, including thermometers, barometers, and other scientific instruments. It is also used in industries such as electronics, where mercury is used in switches and sensors. Additionally, mercury adhesion is crucial in the production of mirrors and other reflective surfaces on glass.

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