Application of a new UV curable adhesive for rapid bonding in thermoplastic‐based microfluidics

This study proposed a rapid and reliable approach for the bonding of thermoplastic‐based microfluidics with a new, low‐cost, low toxic, and transparent ultraviolet (UV) curable adhesive as the intermediate layer between thermoplastic plates. After laser fabrication of microchannels on the surface of the polymethyl methacrylate (PMMA) substrate, the UV curable adhesive layer is applied between the substrate and cover plate; a flushing process is then conducted for the removal of the adhesive residuals inside the microchannel. Finally, a UV exposure with the wavelength of 365 nm is applied for the crosslinking of adhesives to finish the bonding process. Several microfluidic devices were fabricated and tested for the demonstration of the proposed technique, and the bonding strength was carefully measured with different UV exposure duration. The characteristics of the contact angle and UV–visible spectroscopy of the UV adhesive coated surface are also provided in this study. In addition, a simple biocompatibility test of the UV curable adhesive‐coated polymer surface is also conducted in this research to confirm the low toxicity of the adhesive layer. The proposed bonding techniques are broadly applicable to achieve a rapid, low‐cost, optically clear, and low toxic bonding for thermoplastic‐based microfluidics.