On the role of oxygen in fabricating microfluidic channels with ultraviolet curable materials

We present the effects of oxygen on the irreversible bonding of a microchannel using an ultraviolet (UV) curable material of polyurethane acrylate (PUA). Microchannels were fabricated by bonding a top layer with impressions of a microfluidic channel and a bottom layer consisting of a PUA coating on a glass or a polyethylene terephthalate (PET) film substrate. The resulting channel is a homogeneous conduit of the PUA material. To find optimal bonding conditions, the bottom layer was cured under different oxygen concentration and UV exposure time at a constant UV intensity (10 mW cm(-2)). Our experimental and theoretical studies revealed that the channel bonding is severely affected by the concentration of oxygen either in the form of trapped air or permeated air out of the channel. In addition, an optimal UV exposure time is needed to prevent clogging or non-bonding of the channel.This work was supported by the Korea Science & Engineering Foundation through the Nano R & D Program (Grant 2007–02605) and by the Center for Nanoscale Mechatronics & Manufacturing (Grant 08K1401-00210) under the auspices of the Ministry of Education, Science and Technology, KOREA. This work was also supported in part by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (Grant KRF-J03000)