A reliable method for bonding polydimethylsiloxane (PDMS) to polymethylmethacrylate (PMMA) and its application in micropumps

Poly(methylmethacrylate) (PMMA) attracts growing interest in microfluidics research community due to its low cost, high transparency, good mechanical and chemical properties. The more flexible polydimethylsiloxane (PDMS) is well suited for pneumatic actuation. However, PDMS is permeable to gases and absorbs molecules from the sample liquids. Combining PMMA with PDMS would allow a microfluidic device to utilize advantages of both materials. Bonding PMMA to PDMS is a critical step for this hybrid approach. In this paper, we present a simple, fast and reliable technique for bonding PMMA to PDMS. A 25 μm thick adhesive film (ARclear® Optically clear adhesive 8154, Adhesive Research, Glen Rock, PA USA) was laminated onto a clean PMMA surface. Subsequently, pre-cured PDMS mixture was spin coated onto the adhesive film. After curing, the adhesive and the PDMS layer form a hybrid membrane. The bonding quality and the strength of the PDMS/adhesive membrane was tested using a precision pressure source. A peristaltic micropump was fabricated by bonding a PDMS part with microchannels to the PDMS/PMMA part. The PDMS/adhesive membrane acts as the pneumatic actuator for the micropump. Pressurized air was switched to the three pneumatic actuators by solenoid valves and control electronics. The micropumps can achieve a flow rate as high as 96 μl/min. The techniques reported in this paper allow the integration of microfluidic components made of both PMMA and PDMS in a single device.