28 Feb 2019Microfluidic mixers are useful instruments for the investigation of fast (bio)chemical reactions, as they allow time-resolved measurements using small sample volumes. Many reactions, especially those leading to nucleation and growth of nanoparticles, pose problems for microfluidic systems, as the reaction products have a tendency to aggregate and stick to the channel walls, known as the fouling of the reaction. Aggregates invalidate the gathered data and may clog the device by obstructing the channel. The goal of this project was to develop a mixer employing 3D-sheathing to prevent channel blockage, by inhibiting aggregation at the channel walls. We report here on the development of a micromixer geometry that would accomplish the 3Dsheathing behavior. Despite the ease in devising the necessary peripheral systems to perform experiments, the realization of the mixer itself proved to be more difficult. We found that both the correct design of the mixing part and the precision in the fabricated channels are crucial for this approach. We tested a number of materials and production methods to determine an optimal mixer geometry that should achieve the desired 3D-sheathing The precision of the channels we have produced thus far has inhibited the satisfactory function of the instrument. Measurements could be conducted with the prototype, but after some time the lacking precision still led to recirculation and agglomeration. We are currently working towards the improvement of the channels and the channel profile to resolve the remaining problems. Research performed as part of this project has been presented at the MNE2017 conference and the ÖPG Tagung 2018, and been published in Microelectronic Engineering. The development of the prototype itself has been presented on various occasions, e.g. SAXS Excites 2017, Nesy 2019.
28 Feb 2019In today's competitive world of science efficient analysis tools are indispensable. The tools should be instruments providing measurements of small sample amounts, being both cost and time effective. Measurements should be not only easy and fast to execute, but also reliable and precise. Here we report on a new instrument, which enables measurements in a routine and automated way for the high throughput screening of liquid samples. The instrument is an automatic sample changer feeding a novel sample holder for volumes in the range of 5-20 μL. The general operating principle of the sample holder not only allows for precise measurements of very small volumes, but also the reduction of sample quality. High surface-tovolume effects easily occur in more conventional systems based on pumping the sample through tubing into capillaries. While avoiding such high surface-to-volume effects the automatic sample changer enables the measurement of hundreds of samples without requiring of manual intervention. We extensively tested the instrument and showed that it satisfies the initial specifications. It quickly provides reliable, high-quality data using minimal volumes of sample. This new instrument greatly simplifies and accelerates experiments, constituting therefore a valuable contribution for accessing large scale infrastructures. The prototype is already available for testing during general user access at the Austrian SAXS beamline at the Elettra-Sincrotrone Trieste (first experiments are scheduled within March and April 2019) and later on in the NFFA workpackage TNA4. The development of the instrument has been reported at several conferences, including MNE2017, OEPG 2018, NESY Winterschool 2017 and 2019. A publication concerning the system and its testing is currently in preparation.
28 Feb 2019With the drastic need for renewable energy sources, materials with solar harvesting capabilities receive increasingly attention for technological and scientific purposes. In such energy-conversion materials, the principal interaction between light and matter occurs on the nanometer level – a regime in which most properties of bulk-matter do not hold. A comprehensive understanding of these phenomena, particularly the structural material response within the first pico- and nanoseconds after the absorption of light, is critical for the design of novel nanomaterials with enhanced energy conversion efficiency. Deliverable 9.4 aims at building a time-resolved opticalpump X-Ray-probe setup, capable of studying the picosecond lattice dynamics of nanomaterials. This is achieved by installing an ultrafast high-repetition-rate laser at the AustroSAXS beamline of the Elettra synchrotron, where X-Ray scattering / diffraction patterns are taken before, during and after optical excitation. Pilot-experiments were successful, paving the way for accessibility by future NFFA-Europe users.