[success]

Hi, is there anyone know what makes an emulsion stable? What are the properties of the emulsifiers which
lead to stability, and why is temperature important to ageing?

[Biopolmonkey]

With regards to stability ... What are the properties of the two things you are trying to mix? What properties would be advantageous for an emulsifier (aka detergent, surfactant etc) to have in order to interact with both?

[success]

What if it is oil and water?

[Biopolmonkey]

Ok ... Do you know what the property is when a molecule is both hydrophilic and hydrophobic?

(As a hint, do you know anything about cell membranes? Very, very similar to what an emulsifier does - look at micelles as well, in fact, these are more relevant)

AFAIK, emulsifiers always stabilise oil in water, or the reverse.

[young youth]

why?

[success]

What if it's both liquids?

[Biopolmonkey]

... I assumed they were liquids.

What I'm trying to do, unsucessfully, is to make you think of the term amphiphilicity. Basically, this is where a molecule has both hydrophilic (water loving) and hydrophobic (water hating) domains. This is what enables emulsifiers to stabilise oils in water (or vice-versa).

These are often arranged so that there is a hydrophilic 'head', and a long fatty hydrophobic 'tail' - a really common example are the phospholipids that constitute our own cell membranes. (Google will probably have nice images)

Now that I have started you off, look up for yourself micelles and the critical micelle concentration ... see if that helps any.

[evilrabbi]

surfacetant must be needed , if you want to mix oil and water, and others like these.
the surface tension of liquid(water) would be reduced, obviously. other words, resistence preventing to mix is reduced