title: High-grade optical polydimethylsiloxane for microfluidic applications.
abstract: Commercially available polydimethylsiloxane (PDMS) elastomers, such as Sylgard 184® are widely used in soft lithography and for microfluidic applications. These PDMS elastomers contain fillers to enhance their mechanical stability. The reinforcing fillers, often sub-micrometer small SiO(2) particles, tend to aggregate, swell with water, and thereby become cognoscible in a way that can strongly interfere with the visualization of micro-scale events taking place next to PDMS structures. As PDMS microfluidics are often used for studying cells and micro-/nanoparticles and for creating/handling nanodroplets, it has become highly desirable to employ a PDMS having high optical quality and that allows microscopy observation without artifacts. Here, we present a PDMS formulation that is free of fillers and has sufficiently low viscosity to perform a filtration step of the mixed prepolymers before curing. By molding a bi-layer microfluidic network (MFN), composed of a thin filler-free PDMS layer and a thicker Sylgard 184® backing layer, PDMS MFNs featuring both high optical quality and mechanical stability, can be fabricated.
authors.affiliation: IBM Research GmbH, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
authors.forename: Robert Dean
authors.initials: RD
authors.lastname: Lovchik
authors.forename: Heiko
authors.initials: H
authors.lastname: Wolf
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Delamarche
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004129:Dimethylpolysiloxanes / Q000138:chemical synthesis / Q000737:chemistry*; D008420:Manufactured Materials; D051379:Mice; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D017628:Microglia / Q000166:cytology / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry; D053770:Nanowires; D014783:Viscosity
chemical_list: D004129:Dimethylpolysiloxanes