A bonding method between poly(lactic acid) (PLA) and poly(methyl methacrylate) (PMMA) for microfluidic chips

This article presents a novel method to bond poly(lactic acid) (PLA), a 3D-printing material, and poly(methylmethacrylate) (PMMA), a popular substrate material for microfluidic applications. With this technique, the tubing connectors can be fabricated by 3D printing and make this PMMA/PLA hybrid microfluidic chip extremely easy to use for experiments. The mechanism behind this method is based on the polymer dissolution, molecular diffusion, and re-crosslinking of polymer chains. The major challenge of bonding this hybrid chip is the high level surface roughness of PLA substrates with its significant influences on bonding strength [1]. After Ethanol treatment and UV irradiation of this hybrid chip, a post-annealing step was realized to facilitate the bonding. To further analyze the bonding quality, several inspections including leakage test, cross-sectional image by microscope, and pressure bursting test were conducted. The experiment results clearly showed that this method could successfully and rapidly form a strong bond (over 13 bars) between PLA and PMMA substrates.