It is commonly believed that fine oil/water emulsions can be prepared with minimum shear only when sufficient surfactant is available to cover the oil/water interface. For microemulsions of oil and water that form spontaneously, this often means adding comparable amounts of surfactant and oil, and even then, slight changes in temperature and composition can lead to catastrophic destabilization.

Abandoning the notion that the oil/water interface must be covered by an amphiphile that likes both oil and water, we have discovered an alternative low-shear route to forming nanoscale oil-water dispersions. Because of the incompatibility that arises when hydrophobic silica precursors such as tetraorthosiloxane (TEOS) is turned hydrophilic by hydrolysis, balanced reaction/transport conditions exist wherein crude emulsions transform into optically transparent solutions of ~10 nm silica-encapsulated oil drops. Unique features of this process that makes it valuable in a multitude of applications include:

1. High oil loading (>20 wt%)

2. Low amphiphile concentrations (just above CMC)

3. Works with almost any amphiphile (cationic, anionic, non-ionic)

4. Resulting nanoemulsions can be diluted, concentrated, or mixed with almost any other aqueous solution without phase separation of the oil

5. All components are low cost, commercially available, and safe

6. Process is simple and scalable

In essence, this new approach for making nanometer-size capsules and mixing oil with water has all the desirable properties of microemulsions without the disadvantages that have thwarted their large-scale application.