Surface Tension at Critical Temperature: Contact Angle?

In summary, surface tension is a physical property of liquids that describes the force acting on the surface due to cohesive forces between molecules. At critical temperature, this force reaches its minimum value and the liquid becomes less resistant to deformation. The surface tension at this temperature can be measured using techniques like the Wilhelmy plate method, and the contact angle becomes zero, indicating complete wetting of the solid surface. This decrease in surface tension affects the behavior of liquids, making them more fluid and less cohesive. Factors such as chemical composition, impurities, and external factors like pressure and temperature can influence the surface tension at critical temperature.
  • #1
i_island0
123
0
At critical temperature, the surface tension becomes zero.
What happens to contact angle at critical temperature?
 
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  • #2
It's probably not a meaningful concept. Since there is no energy cost associated with creating a material interface (and no pressure jump across a curved surface) it's not clear what 'wetting' means.
 
  • #3
thx.. i think my understanding is getting better now
 

1. What is surface tension at critical temperature?

Surface tension is a physical property of liquids that describes the force acting on the surface of a liquid due to the cohesive forces between its molecules. At the critical temperature, the surface tension of a liquid reaches its minimum value and the liquid becomes less resistant to deformation.

2. How is surface tension at critical temperature measured?

The surface tension at critical temperature can be measured using various techniques such as the Wilhelmy plate method, pendant drop method, or capillary rise method. These methods involve measuring the force required to deform the surface of the liquid, which is then used to calculate the surface tension value.

3. What is the significance of contact angle in surface tension at critical temperature?

Contact angle is the angle formed between the surface of a liquid and a solid surface in contact with it. At the critical temperature, the contact angle becomes zero, indicating that the liquid completely wets the solid surface. This is due to the decrease in surface tension at this temperature.

4. How does surface tension at critical temperature affect the behavior of liquids?

The decrease in surface tension at critical temperature results in a change in the behavior of liquids. They become more fluid and less cohesive, making them easier to deform or mix with other substances. This can also affect the wetting and spreading behavior of liquids on different surfaces.

5. What factors can influence the surface tension at critical temperature?

The surface tension at critical temperature can be influenced by various factors such as the chemical composition of the liquid, the presence of impurities or additives, and external factors such as pressure and temperature. These factors can affect the strength of the cohesive forces between the liquid molecules, thus altering the surface tension value.

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