(91a) Fabrication and Application of Closed-Faced Microfluidic Devices

Microfluidics is a quickly growing technology finding applications in life sciences and pharmaceuticals. The small quantities of solvents used in the devices make them ideal for expensive materials. These cutting edge applications make understanding important to chemical and biomedical engineers. Our work has been in developing a comprehensive protocol for the fabrication of closed-faced microfluidic devices at Bucknell so they can be used in the study of fluid mechanics. These devices are created by placing optical adhesive that can act as a negative tone photoresist between two glass slides with spacers of 650 microns to define the channel height. A mask of the desired pattern, with channels between 200 and 1000 microns, is placed on top and the device is exposed to UV light. The optical adhesive crosslinks upon exposure to the UV light and the unexposed adhesive is washed away with various solvents. The device is then post-cured with UV light and finally baked in an oven. Unlike the open-faced polydimethylsiloxane (PDMS) devices, the closed faced devices are resistant to many organic solvents. This advantage allows for the study of organic and aqueous fluid mechanics on a micro-scale. Specific examples include viewing flow regimes with the chemiluminescence reaction of luminol and the bubbling of two colored toluene streams into an aqueous stream to observe the mixing of the bubbles.