Fabrication of poly(methyl methacrylate) microfluidic chips by redox-initiated polymerization

In this report, a method based on the redox-initiated polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. MMA containing 2-2'-azo-bis-isobutyronitrile was allowed to prepolymerize in a water bath to form a viscous prepolymer solution that was subsequently mixed with MMA containing a redox-initiation couple of benzoyl peroxide/N,N-dimethylaniline. The dense molding solution was sandwiched between a silicon template and a piece of 1-mm-thick PMMA plate. The polymerization could complete within 50 min under ambient temperature. The images of raised microfluidic structures on the silicon template were precisely replicated into the synthesized PMMA substrate during the redox-initiated polymerization of the molding solution. The chips were subsequently assembled by the thermal bonding of the channel plates and the covers. The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating PMMA microdevices. The attractive performance of the novel PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.