What is the proper way to use polysorbate to create an emulsion?
From what I have read, the process is to mix polysorbate with the essential oil, in a 1:1 ratio, until a clear solution is achieved.  Then, add that mixture to your water or flavor syrup. As I understand it, there are several variables, such at pH, temperature, and the other ingredients that might be part of your final product, which could impact the effectiveness of polysorbate.

You could also look into soy lecithin as a potential emulsifier for your situation.