(539d) Implementation of in Situ SAXS/Waxs Analysis in Silicon-Pyrex Microreactor

Optically transparent integrated microfluidic devices are widely used in biology, chemistry and material science mainly because optical in situ characterization, such as microscopic observations, dynamic light scattering, or light spectroscopy (UV-vis, Raman, photoluminescence), can be easily performed inside microchannels. Additionally, thanks to the advancement of synchrotron sources, Small-Angle and Wide-Angle X-ray scattering (SAXS/WAXS) studies utilizing microfluidic devices are more and more used, notably to characterize the morphology and the structure of proteins, nucleic acids, biomacromolecules, or inorganic nanoparticles. Although conventional transparent microfluidic systems (PDMS, PMMA, COP, PS) make excellent prototypes, they have limited operating pressure and temperature ranges, as well as poor chemical compatibility with most of the organic solvents. Alternative experimental setups can overcome some of the above difficulties by considering glass or sapphire capillaries. Their high compatibility with many organic solvents and their good resistance to aggressive chemicals extends the scope of fluids that can be used. However, glass tubings suffer from a low design flexibility and exhibit poor heat transfers. Additionally, it is extremely difficult to design fancy mixing devices in a glass capillary. The development of on-chip silicon/glass microsystems has addressed the optimization of both the experimental approaches towards the use of a large panel of fluids and solvents, as well as the extent of the operating conditions of these microsystems at high temperature and high pressure. This oral presentation will highlight the successful implementation of in situ X-ray scattering analysis of synthetized particle materials in silicon/glass microreactors is reported. Calcium carbonate (CaCO₃) as a model material was precipitated inside the microchannels. The synthesized calcite particles were analyzed in situ in aqueous media by combining Small Angle X-ray Scattering (SAXS) and Wide Angle X-ray Scattering (WAXS) techniques at the ESRF ID02 beam line. We will in particular focus on the benefits of such approaches for accessing continuously nano/micromaterials characteristics (shape, crystalline structures). This study demonstrates that silicon/glass chips are potentially powerful tools for in situ SAXS/WAXS analysis and are promising for studying the structure and morphology of materials in non-conventional conditions including high pressure and high temperature.