A Method to Realize Controlled Air/Liquid Interfaces and Interfacial Polymer Micro Membranes in Microfluidic Channels

In this study, stable air/liquid interfaces and high-aspect ratio polymer micro membranes with complex and controlled structures were formed within microfluidic channels. The air/liquid interfaces were formed at hydrophilic/hydrophobic boundaries defined by patterned and alkanethiols treated Cu surfaces. The two-phase interfaces were further utilized for interfacial polymerization with two immiscible liquid phases containing the reagents for polymer membrane in the microchannel, to generate polymer micro membranes with not only complex in-plane shapes but also z-direction configurations. To demonstrate this method, high quality and complex nylon membranes were fabricated in microchannels. Straight membranes as long as 15mm, 50 mum thick and 500 mum tall in a microfluidic channel were successfully fabricated, and membranes with different structures were realized.