The Fabrication of Poly(Methyl Methacrylate) (PMMA) Microfluidic Chips by Laser Patterning and Electrohydrodynamic (EHD) Printing
X. Yang, Z-F. Yin, L. LI and H-L. Zou
Laser patterning can fabricate complicated microchannels with low cost and high efficiency in poly(methyl methacrylate) (PMMA) sheets; however, the PMMA tends to peak near the laser fabricated microchannels and PMMA substrates always deforms after laser patterning. With such protrusions and deformation PMMA chips cannot be fully bonded and leakage usually occurs in the following filling process. Herein we describe an electrohydrodynamic (EHD)-assisted polypropylene (PP)-PMMA bonding method to solve these issues. The influence of cover plate material and its thickness on the maximum stress in PMMA substrate was investigated. According to the numerical simulation results, 0.4 mm thick PP cover plate can be thermally bonded to the PMMA substrate with minimum stress and unbounded area. The tensile tests and leakage tests show that the bonding strength of PP-PMMA chip can be 0.75 MPa and no leakage occurs over the entire chip.
Keywords: CO2 laser, poly(methyl methacrylate) (PMMA), polypropylene (PP), microfluidic chip, microchannels, laser patterning, electrohydrodynamic (EHD) printing, thermal bonding, numerical simulation, finite element (FE), stress