Microfluidic channel fabrication by PDMS-interface bonding

• Published in: Smart materials and structures Vol. 15; no. 1; pp. S112 - S116
• Main Authors: Chow, Winnie Wing Yin, Lei, Kin Fong, Shi, Guangyi, Li, Wen Jung, Huang, Qiang
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.02.2006; Institute of Physics
• Subjects: Applied fluid mechanics; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Physics; Dimethylsiloxane polymer; Embossing; Ducts; Tensile tests; Interdiffusion; Plastic packaging; Wafer bonding; PMMA; Spin-on coatings; Hot forming; Micromanipulation; Microfluidics; Low temperature; Fluidics
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/15/1/018

A novel technique for bonding polymer substrates using PDMS-interface bonding is presented in this paper. This novel bonding technique holds promise for achieving precise, well-controlled, low temperature bonding of microfluidic channels. A thin (10-25 mum) poly(dimethylsiloxane) (PDMS) intermediate layer was used to bond two poly(methyl methacrylate) (PMMA) substrates without distorting them. Microchannel patterns were compressed on a PMMA substrate by a hot embossing technique first. Then, PDMS was spin-coated onto another PMMA bare substrate and cured in two stages. In the first stage, it was pre-cured at room temperature for 20 h to increase the viscosity. Subsequently, it was bonded to the hot embossed PMMA substrate. In the second stage, PDMS was completely cured at 90 deg C for 3 h and the bonding was successfully achieved at this relatively low temperature. Tensile bonding tests showed that the bonding strength was about 0.015 MPa. Microfluidic channels with dimensions of 300 mum X 1.6 cm X 100 mum were successfully fabricated using this novel bonding method.