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Mixing oil and water

  1. Mar 27, 2005 #1
    This is what I found on a link in {}. If this is already posted feel free to delete. I'm still learning...
    {Thursday, 3 March 2005

    Oil and Water

    It’s a basic fact of science: oil and water don’t mix. Well an Australian scientist refused to accept this standard of chemistry and cooking. He’s developed a method to bring the two together and he’s attracted world attention. It’s not just about better salad dressing, the technique means clothes could be cleaned with just water – no detergent, and insoluble drugs could be delivered quickly and safely inside your body. (full transcript...)

    Reporter: Karina Kelly

    Producer: Richard Corfield

    Researcher: Lucy Andrew
    Story Contacts:

    Professor Ric Pashley
    Australian National University

    Full Program Transcript:

    Anyone who's made a salad dressing can tell you that oil ... and water ... don't mix.

    You can stir them ...

    You can shake them ...

    You can agitate them in all manner of ways ... but they'll always separate out into two distinct layers.

    Ric Pashley
    You ought to be able to make particles or droplets of oil float around in water and we call that disperse. We ought to be able to do that, yet we can't. The oil droplets don't naturally disperse as little fine droplets into the water. But they should and it worried me for some time why that doesn't happen.

    Professor Ric Pashley is passionate about challenging well accepted theories in science. He wanted to see what was stopping oil and water mixing so he took a single drop of oil and pulled it apart in water.

    At the point where the droplet broke in two, he observed gas bubbling out of the water forming a bridge between the droplets and drawing them back together. He wondered : were the oil droplets actually surrounded by a layer of gas all the time? Could this gas layer be what stops the oil and water mixing?

    All liquids, everywhere, contain gases, which dissolve in from the atmosphere. It's a fact of nature.

    Ric wondered if removing the gas from the oil and water layers would change their mixing properties.

    He froze the sample, using liquid nitrogen.

    On thawing you can actually see the dissolved gas bubbling out. There's quite a lot!

    Ric Pashley
    About 20 ml of gas is dissolved in a litre of water so it's a not insubstantial amount.

    After four or five cycles of this freezing and thawing, the sample is now gas free.

    It looks cloudy because the water is now saturated with tiny oil droplets, the excess left floating on the surface.

    They'd mixed the metaphor. Oil and water do mix. All you have to do is remove the gas. It's so simple.

    Ric's discovery is set to revolutionise many industrial processes in food production, perfumery and drug manufacture.

    Many drugs used in hospitals are oily. To get them into the bloodstream they have to be mixed with detergents or solvents, which themselves can have nasty side effects.

    Ric's process means that oily drugs can be mixed directly into water, without additives. What's more, the drugs are now tiny droplets, just 0.3 micron across, making them perfect for the body to absorb.

    While there's years of human trials ahead, the technique could be used right now to test the active ingredients in new drugs without the complication of additives.

    Ric Pashley
    Now in that form the drug could be screened. That is whether the drug has any action as a anti-cancer drug or whatever and I think that is a fairly rapid and immediate advance in what we've done.}
  2. jcsd
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