The effect of wettability on microfluidic EDGE emulsification was investigated at dispersed phase contact angles between 90 degrees and 160 degrees. The highest contact angle (160 degrees) produced monodispersed emulsions with droplet size 5.0 mu m and coefficient of variation <10%; however, pressure stability was very low. This was greatly enhanced at contact angles <150 degrees; 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 degrees due to wetting with the dispersed phase. (C) 2013 Elsevier Inc. All rights reserved.