The use of UV/ozone surface treatments for achieving low temperature bonds between PMMA and COC microfluidic substrates is evaluated. Low temperature bond strengths, approaching those of native polymer substrates bonded above their glass transition temperatures, are demonstrated for both thermoplastics. To evaluate the effects of the UV/O(3) surface treatment on the operation of bonded microfluidic devices, the relationship between UV/O(3) exposure and polymer hydrophilicity and surface chemistry are measured. Post-treatment surface chemistry is evaluated by XPS (X-ray photoelectron spectroscopy) analysis, and the stability of the treated surfaces following solvent exposure is reported. Electroosmotic flow within fabricated microchannels with modified wall surfaces is also characterized. Overall, UV/O(3) treatment is found to enable strong low temperature bonds between thermoplastic microfluidic substrates using a simple, low cost, and high throughput fabrication technology.
The measurement of single poly(ethylene glycol) (PEG) molecules interacting with individual bilayer lipid membrane-bound ion channels is presented. Measurements were performed within a polymer microfluidic system including an open-well bilayer lipid membrane formation site, integrated Ag/AgCl reference electrodes for on-chip electrical measurements, and multiple microchannels for independent ion channel and analyte delivery. Details of chip fabrication, bilayer membrane formation, and alpha-hemolysin ion channel incorporation are discussed, and measurements of interactions between the membrane-bound ion channels and single PEG molecules are presented.
A robust and low dead volume world-to-chip interface for thermoplastic microfluidics has been developed. The high pressure fluidic port employs a stainless steel needle inserted into a mating hole aligned to an embedded microchannel, with an interference fit used to increase pressure resistance. Alternately, a self-tapping threaded needle screwed into a mating hole is also demonstrated. In both cases, the flat bottom needle ports seat directly against the microchannel substrate, ensuring low interfacial dead volumes. Low dispersion is observed for dye bands passing the interfaces. The needle ports offer sufficient pull-out forces for applications such as liquid chromatography that require high internal fluid pressures, with the epoxy-free interfaces compatible with internal microchannel pressures above 40 MPa.
In low earth orbit [LEO] satellite applications, spacecraft power is provided by photovoltaic cells and batteries. To overcome battery shortcomings, FARE, Inc., working in cooperation with the University of Maryland [UOM] and the NASA Lewis Research Center, has developed an open core magnetically-suspended graphite-epoxy flywheel for energy storage applications. This flywheel energy storage system, called the Open Core Rotator [OCR], was designed to meet specifications set forth by NASA. NASA's primary design requirement called for an OCR system capable of delivering 50 Wh of energy. FARE's OCR is based on and builds upon the fundamental research that has been carried out at the University of Maryland since 1977. The UOM presently has an operational 500 Wh Open Core Composite Flywheel [OCCF]. FARE's OCR is a scaled-down version of the UOM's OCCF.Spec~cally, this paper discusses the procedure followed by FARE in designing its 50 Wh OCR, including how the resdtant dimensions and component topology were obtained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.