Rapid-release reversible bonding of PMMA-based microfluidic devices with PBMA coating

PMMA-based microfluidics have been widely used in various applications in biological and chemical fields. In the fabrication process of PMMA-based microfluidics, the substrate and cover plate usually need to be bonded to enclose the microchannel. The bonding process could be permanent or reversible. In some application scenarios, reversible bonding is needed to retrieve the samples inside the channel or reuse the chip. Current reversible bonding methods for PMMA-based microfluidics usually have drawbacks on bonding strength and contaminations from the adhesives used in the bonding process. In this study, a new approach is proposed for the reversible bonding of PMMA-based microfluidics, a layer of PBMA (with a very similar structure to PMMA) was coated on the surface of PMMA and then use the thermal fusion method to achieve the bonding with a high bonding strength, a tensile bonding strength of around 0.8 MPa was achieved. For debond process, a rapid temperature drop will trigger the immediate release of the bonding within several seconds. Detailed bonding strength measurement and biocompatibility tests were also conducted in this study. The proposed bonding method could have wide application potential in the fabrication of PMMA-based microfluidics.