Novel solvent bonding method for creation of a three-dimensional, non-planar, hybrid PLA/PMMA microfluidic chip

Fused deposition modeling (FDM) is an approach of 3D printing and has been used in the fabrication of microfluidic systems. Unfortunately, the poor optical transparency of the resulting microfluidic devices makes the characterization and quantification of experiment results difficult. In this study, we developed a method of solvent bonding PMMA and poly(lactic acid) (PLA) thermoplastic materials for the creation of hybrid microfluidic chips. The benefits of the proposed method are as follows: (1) simplified fabrication of complex 3D microfluidic chips; (2) optical characterization and quantification of fabrication results; and (3) the ability to print and embed tubing connectors within the microfluidic chip to facilitate assembly. Three experiments were conducted to evaluate the efficacy of the proposed scheme. We fabricated one microfluidic chip with an S-microchannel to examine the fundamental fabrication results. We also fabricated two application-oriented microfluidic chips respectively featuring a 3D non-planar micromixer and a double emulsion generator. Our experiment results demonstrate the efficacy of this bonding method in the rapid formation of strong bonds (exceeding 13 bars) between PLA and PMMA substrates. The two application examples further demonstrate that the proposed scheme is applicable to the fabrication of complex microfluidic chips quickly and easily without sacrificing their intended functionalities.