Method for producing high dielectric strength microvalves
AssigneeSandia National Laboratories
InventorsBrian J. Kirby, David S. Reichmuth, Timothy J. Shepodd
Life of this patent
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Abstract
A microvalve having a cast-in-place and lithographically shaped mobile, polymer monolith for fluid flow control in microfluidic devices and method of manufacture. The microvalve contains a porous fluorinated polymer monolithic element whose pores are filled with an electrically insulating, high dielectric strength fluid, typically a perfluorinated liquid. This combination provides a microvalve that combines high dielectric strength with extremely low electrical conductivity. These microvalves have been shown to have resistivities of at least 100 GΩ and are compatible with solvents such as water at a pH between 2.7 and 9.0, 1-1 propanol, acetonitrile, and acetone.
Claims10
A method for producing a mobile polymer monolith whose pores are substantially filled with an electrically insulating, high dielectric strength fluid, comprising:
- providing a microchannel structure;
- injecting a mixture comprising a fluorinated solvent, a singly-functional fluorinated monomer, a multiply-functional fluorinated cross-linker, and a polymerization initiator into said microchannel structure;
- photoinitiating localized polymerization;
- and
- flushing unpolymerized monomer from the microchannel.
A method for preparing a mobile polymer monolith having pores substantially filled with an electrically insulating, high dielectric strength fluid, comprising the steps of:
- providing a wet-etched glass microfluidic chip having a microchannel structure;
- injecting a 1:1:1 mixture comprising a perfluorinated solvent, the monomer heptafluorobutyl acrylate, the crosslinker 2,2,3,3,4,4,5,5 octafluoro 1,6 hexanediol diacrylate, and 1% 2,2′ azobisisobutyronitrile by weight into the microchannel;
- photoinitiating localized polymerization by irradiating a portion of the mixture with the 355 nm emission from a 12 kHz, 800 ps-pulse, 160 nJ-pulse, frequency-tripled Nd:YAG laser;
- and
- flushing unpolymerized monomer from the microchannel.
Dependencies are inferred from the claim text.