It is hard to permanently seal the microfluidic channels made of thermoset polymers without using conventional adhesives. Here, we reported a polyaddition-based mechanism to solve the problem. The method is based on introducing amine groups onto the surface of one material and epoxy groups on another material and enabling the amine-epoxide polyaddition reaction at their closely contacted solid-to-solid interface to establish a covalent and permanent bonding. It was successfully used to permanently seal polydimethylsiloxane (PDMS) microfluidic channels with glass in a scalable and multifunctional fashion and to seal epoxy (SU-8) microfluidic channels with PDMS. This type of interfacial polyaddition can be easily extended to other materials for microfluidic device fabrication and is expected to find some applications in specialty bonding. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.