From page 6–discussion of plasma surface activation and the bonding of glass and PDMS
Microfluidic chips were manufactured by conventional soft lithography.27 Molding masters were fabricated by spin coating
SU-8 negative photoresist (MicroChem Corp., Newton, MA) onto 6 inch silicon wafers and transferring the fluidic features
from photomasks (CAD/Art Services, Bandon, OR) by contact lithography with an OAI Hybralign Series 200 aligner (OAI, San
Jose, CA). Chips contained channels with two depths: deep channels with low hydrodynamic resistance (100 _ 10 mm) for
transporting fluid from external ports to the functional regions of the chip, and shallow channels (20 _ 1 mm) for droplet manipulation and detection. SU-8 photoresists 2100 and 2025 were used for deep and shallow channels respectively. Polydimethylsiloxane
(PDMS) (Sylgard_ 184, Dow Corning, Midland, MI) chips were molded from the negative masters
within mold housings of custom design. Glass cover slides were permanently bonded to the fluidic side of the chips by
plasma surface activation in an AutoGlow oxygen plasma system (Glow Research, Phoenix, AZ) followed by immediate contact bonding.
To create hydrophobic surfaces, the microfluidic channels as well as the fluid-exposed surfaces of the emulsion vials (see Fig. 1)
were treated for _2 min with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (Alfa Aesar, Ward Hill, MA) dissolved in FC-3283
(3M Specialty Materials, St Paul, MN) prepared as a mixture of18 g silane in 100 mL solvent.
From: Lab on a Chip: site this: Lab Chip, 2011, 11, 2167
Qun Zhong,a Smiti Bhattacharya,a Steven Kotsopoulos,a Jeff Olson,a Valerie Taly,b Andrew D. Griffiths,b
Darren R. Linka and Jonathan W. Larson*a
For more information on the Glow Research AutoGlow plasma system: http://www.glowresearch.org/autoglow-plasma-system