Surface treatment of flow channels in microfluidic devices fabricated by stereolithography

A microfluidic device with three-dimensional flow channels was fabricated by stereolithography, and hydrophilic surface treatment of the flow channel was performed by coating the wall of the channel with a silica layer. After the treatment, the device produced monodisperse oil-in-water (O/W) emulsions. The silica layer on the channel surface was then coated with a fluorinated silane coupling agent to make it hydrophobic, thus enabling the treated device to produce monodisperse inverted water-in-oil (W/O) emulsions.