Nanofluidic system with electrochemical and flow mixing capabilities for in-liquid electron microscopy studies - Phase I

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The study of in-liquid samples with nanometre and potentially down to atomic resolution requires the integration of a very specialized nanofluidic cell system (NFCS) into the electron microscope in order to enable transmission electron microscopy (TEM) and electron diffraction/scattering (TED) measurements. A NFCS is therefore a high-tech device (or TEM accessory) capable of manipulating and delivering tiny amounts of liquid to the electron beam path for observation. The NFCS comprises and a nanofluidic cell (NFC) and a nanofluidic holder (NFCHs), which are mutually sealed to prevent liquid leaks and preserve the vacuum integrity inside the electron microscope column. The designs of NFCSs are conceptually simple; however, achieving true control of the liquid flow, and up to some extend of the thickness of the liquid layer across the viewing windows of the NFC continues to be an unsolved challenge for current NFCS manufacturers. The strongly interacting nature of electrons with matter leads to the necessity of implementing a very short electron beam (often within 100 nm - 1000 nm) with very thin silicon nitride films (10 nm - 100 nm) as windows. Although capillary forces may initially help, the reduced cross-sectional area of the nanochannel creates a large resistance to flow and with that pressure builds up in the inlet. Despite their very high cost, the design of commercial state-of-the-art NFCSs is way too simple to ensure true liquid flow; i.e. the resistance for liquid to flow through the nanochannel is so large that most of the fluid goes around the NFC sandwich while any effort to force the liquid path would lead to window bulging and the deterioration of image quality. UW nanofluidic technology circumvented the aforementioned issues, enabling true control of the liquid flow rate, which in combination with fluid mixing and in situ electrochemistry capabilities will allow for realization of new and exciting in situ TEM experiments. The creation of a start-up in Waterloo region is anticipated (ca. fall 2020).