How do I make a stable water/oil micro-emulsion at home?

[Tracy Hale]

Hi, I'm not a scientist or engineer,, I'm actually an artist, with severely insufficient knowledge in chemistry . I also don't work for a big company that's funding my project, I'm paying for everything myself.
I trying to make a water in oil micro-emulsion at home that does no require any specialized lab equipment, or chemicals that are not easily available to the general public.

The micro-emulsion has an aqueous solution for the dispersed phase, which should be 20-25% of the total volume, It should form micelles 5-50nm and stable at temperatures up to 60c and when subjected to electrical fields. The continuous phase needs to be non conductive, and set to a gelatinous or solid state, either by cooling, UV curing, chemical reaction, etc, as long as it does not evaporate the water phase.What would be workable continuous phase and surfactants?
What would be the steps needed to make the emulsion?

Thanks

 

[Baluncore]

Welcome to PF.
There are many recipes for mayonnaise.
https://en.wikipedia.org/wiki/Mayonnaise

https://en.wikipedia.org/wiki/Mayonnaise#Physical_and_chemical_properties
“By contrast, if the oil and aqueous phases are mixed all at once the result is a water-in-oil emulsion similar in viscosity to the oil from which it is made”.

 

[Tracy Hale]

Hi Baluncore,

I really appreciate you're responding to my question.

It's funny that you mention mayonnaise, because I was making mayonnaise earlier today, for a local food faire. I really think that it's great "out of the box thinking", that you thought of it, but there are several problems with using inverted mayonnaise (or as I like to call it "salad dressing") :

First off it's not a Micro-emulsion
"Micro-emulsion: Dispersion made of water, oil, and surfactant(s) that is an
isotropic and thermodynamically stable system with dispersed domain diameter varying
approximately from 1 to 100 nm, usually 10 to 50 nm."

Second it separates at temperatures below 60c (140f), and the water evaporates.
Third it's a liquid, even if a viscous liquid.

Thanks

 

[Baluncore]

Interesting.
Your requirement for high electrical resistivity and stability in an electric field suggest you are trying to make a dielectric. Those requirements will determine how you preserve the micro emulsion while it sets, if that is what you want it to do.
Why must it have those electrical characteristics and can you specify the values or set the requirements?

If only 20% of the bulk is water then it will be difficult to prevent the water from settling through the oil due to differential density. The surface chemistry of the water drops must also prevent them from coalescing. That may need some complex surface chemistry.

It is probable that you can make the emulsion using mechanical action, maybe in an ultrasonic cleaner. Whatever you do, it will take energy to break up the water and store that energy in the surface of the water particles. It may also be possible to make the emulsion chemically, or from ice. Also consider the possibility of a cloud chamber that repeatedly precipitates a fog of a selected size onto a resin surface that grows.

The oil used will determine the viscosity of the initial emulsion. How solid do you want it to become, can it set hard like an epoxy resin or a glass?
How will the finished micro emulsion be contained? How big will it be, a pins head, a bucket or 1000 kg?

Will the water be a dielectric or a solvent, and why must it be preserved from evaporation? It would help to know what you will use the water for. As a dielectric, water behaves differently when chemically bound in small volumes such as a clay or vegetation. What might be chemically dissolved in the water? That will determine the possible surface chemistry.

Why you want to make it will determine how you will make it and what fluid you will use to support the water.
Sorry about all the question marks.

 

[Tracy Hale]

Interesting.
Your requirement for high electrical resistivity and stability in an electric field suggest you are trying to make a dielectric. Those requirements will determine how you preserve the micro emulsion while it sets, if that is what you want it to do.
Why must it have those electrical characteristics and can you specify the values or set the requirements?

If only 20% of the bulk is water then it will be difficult to prevent the water from settling through the oil due to differential density. The surface chemistry of the water drops must also prevent them from coalescing. That may need some complex surface chemistry.

It is probable that you can make the emulsion using mechanical action, maybe in an ultrasonic cleaner. Whatever you do, it will take energy to break up the water and store that energy in the surface of the water particles. It may also be possible to make the emulsion chemically, or from ice. Also consider the possibility of a cloud chamber that repeatedly precipitates a fog of a selected size onto a resin surface that grows.

The oil used will determine the viscosity of the initial emulsion. How solid do you want it to become, can it set hard like an epoxy resin or a glass?
How will the finished micro emulsion be contained? How big will it be, a pins head, a bucket or 1000 kg?

Will the water be a dielectric or a solvent, and why must it be preserved from evaporation? It would help to know what you will use the water for. As a dielectric, water behaves differently when chemically bound in small volumes such as a clay or vegetation. What might be chemically dissolved in the water? That will determine the possible surface chemistry.

Why you want to make it will determine how you will make it and what fluid you will use to support the water.
Sorry about all the question marks.

I understand how it's really hard to answer questions with so little information, but I really don't have much more than you do. This is part of a segmented project that each of us is only given the information to do their part. But I'll try to tell you what I can.

The water is a solvent, and there is a salt dissolved in it the turns the water blue. When the ions are put in an electric field they are supposed to do something (I haven't beed told what), but for that to happen the solution has to be in droplets 20-50nm small.

I't never occurred to me that having too little of the dissolved phase can cause coalescing, I was worried that any more that 20-25% would cause that problem. The water droplets need to be far enough from each other that they don't interact, but there should be as many of them as possible so how much would be enough?

The only think that really matters, about the oil phase is that it holds the water phase in place, and separated it from the conductors. If it remained a viscous liquid the it could be moved by friction causing the conductors to short out. How hard it is doesn't matter as long as it isn't fluid, so it can be elastic or rigid, though it shouldn't be brittle.

 

[Baluncore]

I have to assume that this will need to be a thin sheet material, with a clear electrically conductive layer on one or both sides, like an LC display. I assume the oil phase will need to be transparent to light of an as yet, unspecified spectrum. Will the micro-emulsion be formed on a reflective surface or have a back-light?

With micelles of 5 to 50 nm, with blue light having a wavelength of 470 nm, and with 20 to 25% by volume, there are going to be some interesting refraction or scattering effects. The film will need to be somewhere between 5 and maybe 25 micelles thick to cover the surface. That makes it between 250 nm and 1 um thick. Again that is going to produce wavelength dependent rainbow colours typical of an oil film on a wet surface.

If the emulsion is made in bulk and then spread, will the alignment of the micelles result in refraction effects. If the film was made by deposition in place, it would take several passes to build up the required thickness.

 

[Tracy Hale]

I have to assume that this will need to be a thin sheet material, with a clear electrically conductive layer on one or both sides, like an LC display. I assume the oil phase will need to be transparent to light of an as yet, unspecified spectrum. Will the micro-emulsion be formed on a reflective surface or have a back-light?

With micelles of 5 to 50 nm, with blue light having a wavelength of 470 nm, and with 20 to 25% by volume, there are going to be some interesting refraction or scattering effects. The film will need to be somewhere between 5 and maybe 25 micelles thick to cover the surface. That makes it between 250 nm and 1 µm thick. Again that is going to produce wavelength dependent rainbow colours typical of an oil film on a wet surface.

If the emulsion is made in bulk and then spread, will the alignment of the micelles result in refraction effects. If the film was made by deposition in place, it would take several passes to build up the required thickness.

When reading this, It seems like it has to be totally right on. I was never told that the emulsion needs to be transparent, but I think it that it should not be totally opaque.

Interestingly a few days ago I overheard 2 guys talking about trying to figure out how to spread a micron layer of honey between aluminum foil and saran wrap. It didn't occur to me that they could be part of my project.

What kind of deposition are you thinking of? Remember, this is something that has to be able to be done at home with easily available items.

 

[Baluncore]

What kind of deposition are you thinking of? Remember, this is something that has to be able to be done at home with easily available items.

"Thinking" is the key word. The challenge is keeping the thinking outside the box. I keep thinking of pancakes.