Surface Functionalization and Bonding of Chemically Inert Parylene Microfluidics Using Parylene-A Adhesive Layer

Parylene microfluidic systems have been utilized for applications requiring properties such as high chemical resistance, high internal pressure, high mechanical strength, and small heat loss. However, they have not been widely used compared to PDMS microfluidics because the device fabrication is relatively complex and surface functionalization is difficult. In this work, we introduce a simple and economic fabrication method for parylene microfluidic devices by molding and bonding using thin-film parylene A as an adhesive layer. The amine functional group from parylene A leverages as a covalent bonding source in between two parylene layers while providing the capability of functionalization of the internal surface of parylene microfluidic channel that is highly resistant to harsh chemicals at the same time. This new approach demonstrates the ability of high bonding strength (~ 4 Mpa) and eliminates the use of an additional adhesive polymer layer, which often fails to provide sufficient chemical resistance.