Breaking the surface tension of a droplet within a tube

In summary: Thanks for your suggestion. I have tried it and it does not seem to work. I think I will have to look into electrocapillarity a bit more to see if that is the answer. In summary, capillary action doesn't seem to be able to create a droplet at the end of the tube. Alcohol may be able to break the surface tension and create a droplet.
  • #1
Farnet
9
0
Hi,

I wasn't actually sure where I should post this.

I am trying am experiment where I need to briefly break the surface tension of a droplet to then allow another droplet to form in it's place.

I don't want to use any chemicals as that would effect the test further down the line.

Is there an element that will naturally break the surface tension of water when it is briefly in contact with it?

Basically I can get the water to form a droplet just inside the tube (which is 0.8mm ID) with a concave surface at the end of the tube, but due to its size it will then just sit there (so to speak), and I need it to drain from the tube without using any increased pressure or chemicals...

I have thought of wicking, but that is way too slow (tested it and it does work), although I have been informed that silica strands are far better.

Any help is appreciated.

Cheers

Farnet
 
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  • #2
Just to make it a bit clearer.

I am using capillary action to draw the water horizontally to the end of the tube and even with the tube pointing slightly down there isn't enough force for the water to drip out.

I had a light bulb moment and thought that if I can somehow break the surface tension at the end of the tube, then it might act like a dripping tap.

I don't want to contaminate the water, so I am looking at any way that I can achieve this with no chemical, electrical or mechanical intervention, I have been searching the net for various ideas but I am getting nowhere.

Apologies to those of you who are thoroughbred scientists, this is my pet project and as such not a professional, just budding enthusiast :-)
 
  • #3
I have to say I'm quite surprised no one here has a clue, I was advised to post here as you guys should know the answer, I'll try the physicists...
 
  • #4
I would use a product used to treat bathroom mirrors an render them "fog free". Rain-X makes one.
 
  • #5
Ahh, now that's a good idea.

Thanks Chemistree :-)
 
  • #6
I don't know if it will work but it is a cheap way to see if you are on the right track. The use of silica whiskers is a good idea and it actually might be those that you want to treat rather than the tip of the capillary.
 
  • #7
Or just use a drop of alcohol.
 
  • #8
And not contaminate the water? If you are one of those that believes that alcohol should never be classified a 'contaminant', welcome to my club.
 
  • #9
Hello

Did you mind of electrocapillarity?
May be that a wire at high potential will modify the surface tension doing what you need.

Roberto
 

FAQ: Breaking the surface tension of a droplet within a tube

1. How is surface tension measured in a droplet?

Surface tension is typically measured in units of force per length, such as dynes per centimeter. In the case of a droplet within a tube, it can be measured by using a tensiometer to measure the force required to break the droplet's surface tension.

2. What factors affect the surface tension of a droplet?

The surface tension of a droplet can be affected by several factors, including the type of liquid, temperature, and the presence of surfactants (substances that reduce surface tension). Additionally, the curvature of the droplet and the size of the tube it is contained in can also impact surface tension.

3. How do you break the surface tension of a droplet within a tube?

The surface tension of a droplet can be broken by applying a force that is greater than the surface tension force. This can be done by adding surfactants, stirring the droplet, or gently tapping the tube to create vibrations that disrupt the surface tension.

4. What are the practical applications of breaking the surface tension of a droplet within a tube?

Breaking the surface tension of a droplet within a tube has many practical applications, including in the manufacturing of pharmaceuticals and cosmetics, where precise control of droplets is necessary. It is also important in the study of fluid dynamics and in medical procedures such as blood tests and microsurgery.

5. How does breaking the surface tension of a droplet affect its behavior?

Breaking the surface tension of a droplet can significantly change its behavior. It can cause the droplet to spread out and form a thin film, break into smaller droplets, or merge with other droplets. This can also affect the movement and evaporation of the droplet, as well as its interactions with other substances and surfaces.

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