For the emulsion may affect the startup sequence:

1. Water

2 the surfactant in water.

3.monomer

When administered surfactant monomers should be completely dissolved. If necessary, the solution may be heated. But before introduction of the monomers it is necessary to cool to room temperature.

Best regards.

The essential point you need is contained in the concept of HLB (hydrophile/lipophile balance). 

When one wants a water-in-oil emulsion, one must use a surfactant that is oil-soluble, rather than water-soluble.  This leads one to surfactants with low HLB's, typically less than about 50. 

McCutcheon's catalog of surfactants is an excellent source of HLB values, plus lots of additional information, including identity and source of surfactants.  I suggest you consult that volume to make your selections. 

Try Hypermer 2296 or similar (non-ionic ethoxylated ester-type surfactant (HLB = 4.9))

Some mixed surfactants such as inoic/nonionic surfactants shoud be better for stabilizing these materials.

As you state your problem is Ostwald ripening. Then it would be not a problem of emulsifier but problem of high solubility of water in methacrylate / methacrylic acid. Proven method is to use 'osmotic agent', which could be salt for present case.

I have tried to use different salts such as Magnesium sulphates and Sodium chlorides at different concentrations as osmotic agents. however, this has resulted in phase separation.  

maybe methacrylates are sensitive to electrolytes. Maybe better sugar or glycerol?

I have tried Sucrose, starch and cholesterol. No effect at all on the ripening rate.  

are you sure that it is ripening, i.e. increase in size of water droplets through diffusion?

Any idea what is interfacial tension between methyl methacrylate/methacrylic acid and water.

I think that thickening the oil phase might help to stabilise the emulsion. however, I could find that suitable thickener for the methacrylate.  

maybe by dissolving related oligomers?

Consider the effect of pH on your problem.  MMA has a modest solubility in water, with MAA much higher.  Higher pH's will promote solubilization of the MAA -- suggest you remain below about pH 2 to minimize this effect. 

You don't mention your goal, nor your emulsification process.  I assume you're using mechanical emulsification, in which case you will obtain a broad initial particle size distribution.  Such distributions will inevitably "ripen" to a smaller breadth, with a corresponding increase in mean and median size. 

Two techniques are considered preferable: 

So far I noticed we speak about water in oil emulsion.