Integrated microfluidic platforms on thin transparent membranes

Accelerator-based x-ray spectroscopy and aberration-corrected electron microscopy are workhorse high- resolution tools for the visualizing the structure and chemistry of materials. Without special environmental cells, this technique can only probe static structures because of the ultra-high vacuum requirements of the instrumentation. However, development of battery anodes and catalytic materials requires real-time characterization of liquid and gas-phase chemical dynamics. Liquid cell experiments at x-ray sources or in electron microscopes require that samples be transparent to probe beams, leak tight, and fit in transfer arms for interfacing with the ultra-high vacuum instrument chamber. Moreover, general lack of standardized interfacing with these instruments poses considerable barriers to entry for researchers seeking access to these valuable techniques because of the high capital and labor costs associated with fabricating custom sample holders for each experiment. The central objective is development of chips with electron and x-ray-transparent membrane windows, integrated electrodes, and microfluidic channels with standardized interfacing to compatible sample holders. By relegating any experimental complexity to a consumable and customizable chip, researchers will only need to procure inexpensive chips to perform their experiments, rather than both chips and custom sample holders. In the Phase I program, the team developed the basic fabrication techniques needed to produce chips with thin membranes, monolithic microfluidics, and integrated electrodes. The team measured the pressure resistance of these membranes, which survive beyond four atmospheres of applied pressure. During the Phase II program, the team will mature the product for foundry scale production, validate the device performance at synchrotron x-ray facilities, and extend the fabrication techniques to support future Department of Energy experimental capability. Technology advances in electron and x-ray science have helped lower the capital costs associated with these historically challenging and complex experimental techniques. As these techniques become more widely adopted, there will be a growing need to supply researchers with consumable supplies that facilitate in-situ studies of materials in environmental scenarios. The technology developed within this program will accelerate the feedback loop between capital cost reductions and widespread adoption of these tools and techniques.