Effect of surface wettability on microfluidic EDGE emulsification.

The effect of wettability on microfluidic EDGE emulsification was investigated at dispersed phase contact angles between 90° and 160°. The highest contact angle (160°) produced monodispersed emulsions with droplet size 5.0 μm and coefficient of variation <10%; however, pressure stability was very low. This was greatly enhanced at contact angles <150°; the plateaus filled completely, and the droplet generation frequencies increased up to a factor of 2.0 and 3.5 for Tween20 and Tween60 respectively at the same pressures. The emulsion became highly polydispersed at contact angles <100° due to wetting with the dispersed phase.