The optimization of PDMS-PMMA bonding process using silane primer

In this paper, we present an optimized bonding method to bond PMMA and PDMS substrates. Silane primer was used for the formation of hydroxyl groups on PMMA surfaces. The hydroxyl groups enhanced the bonding strength of PDMS-PMMA substrates without channel clogging or structure deformation. X-ray photoelectron spectroscopy (XPS) analysis was performed to identify the fundamental processes for bonding, which were oxygen plasma, 3-APTES, and corona discharge. We characterized the bonding strength in terms of the tensile strength and the leakage pressure for various surface treatment conditions to find optimal bonding process. The average bonding strength obtained by the optimal bonding process is 2.5 MPa. This bonding process using silane primer can be widely used in the microfluidics of micro-total analysis system and lab-on-a-chips.