When designing food products, it is important to understand and predict structure-function-property relationships within food constituents. This includes knowledge of not only the structure of native materials but also their structural changes across a wide range of length scales brought about by food processing. The inherent complexity of food systems therefore calls for an arsenal of techniques and instrumentation that can access a broad range of dimensions.

The Australian Nuclear Science and Technology Organisation (ANSTO) commenced the ‘Food Materials Science Programme’ to explore opportunities for the utilisation of the nuclear based methods, including small and ultra-small angle neutron scattering ((U)SANS), in a quest to extend the understanding of complex food systems. This presentation will highlight the role of (U)SANS in the context of broader materials characterisation methods, using several examples^1-8.

[1] Elliot Paul Gilbert, Current Opinion in Colloid & Interface Science 42 (2019) 55.

[2] Amparo Lopez-Rubio, Elliot Paul Gilbert, Trends in Food Science and Technology 20 (2009) 576.

[3] James Doutch, Mark Bason, Ferdi Franceshcini, Kevin James, Douglas Clowes, Elliot P. Gilbert, Carbohydrate Polymers 88 (2012) 1061.

[4] Constantinos V. Nikiforidis, Elliot Paul Gilbert, Elke Scholten, RSC Advances, 5 (2015) 47466.

[5] Zhi Yang, Xu Xu, Ravnit Singh, Liliana de Campo, Elliot P. Gilbert, Zhonghua Wu, Yacine Hemar, Carbohydrate Polymers, 212 (2019) 40-50

[6] Yaiza Benavent-Gil, Cristina M. Rosell and Elliot P. Gilbert, Food Hydrocolloids 112 (2021) 106316.

[7] Steven Cornet, Liliana de Campo, Marta Martinez-Sanz, Elke Scholten and Elliot Paul Gilbert, in manuscript

[8] https://www.ansto.gov.au/research/programs/other/food-science

Majority of recent small-angle X-ray scattering (SAXS) studies have been performed mainly in the large-facility, such as SPring-8 (JAPAN), APS (USA), and other synchrotron radiation facilities. Since high intensity of those source makes possible to realize time resolve measurements in a few seconds in non-distractive mode, "operand" measurements become popular and important to understand formation of nanostructures in many materials. In contrast, laboratory SAXS systems are usually regarded as the tool for static measurements. However, recent progress in source, optics (confocal mirror, low scattering slit) and detector makes us possible to measure nanostructure in a few minutes. Those systems can also be optimized for high energy source such as Mo solid or In-rich liquid metal targets. Combining these features, reaction continuing for a few days can be monitored non-destructively, which we call "slow operand" measurements. Two examples will give in this talk; First one is about low temperature aging (room temp., 65ºC, 120ºC) of Al-Zn-Mg-Cu alloys for 2 days. Second example is shape change of colloidal calcium phosphate (CCP) in real cheese for more than 5 days. In the former case, we have measured 1 mm thick aluminum sheet directly from solid solution treatment (SST) without any sample thinig using labo-SAXS with Mo source. We have also measured the sample with rolling following SST. Since all has been done in same room, the uncovered time before starting measurements are less than 5 minutes. Advantage in the second example is the physical distance between source and cheese factory. Since fresh curd (before salting) and cheese has been carried from real cheese factory in Rakuno Gakuen Univ. to labo. SAXS in Hokkaido Univ. with in 1 hour. Samples (curd or cheese) with 1.8 mm thick put into the glass cell and sealed. Shape of nanostructure of cheese corresponding to CCP changes from about sphere of 2.4 nm in diameter to disc like shape with 14 nm in diameter as shown in Fig.1.

Though there are many studies using SAXS [1, 2] including operand measurements in both case, such long time-span measurements have not been reported as far as we know. Nevertheless, there are several processes which are industrially important and occur slowly around room temperature. For those target, the slow operand technique with labo-SAXS must be very useful and important in addition to regular operand technique with large facilities.

Figure 1. Time evolution of SAXS profiles of curd and cheese from 1 hour to 5 days after production . [1] ex. Deschamps, A., De Geuser, F., Horita, Z., Lee, S. & Renou, G., (2014). Acta. Mater. 66, 105[2] ex. Ingham, B., Smialowska, A., Kirby, N. M., Wang, C. & Carr, A. J. (2018). Soft Matter. 14, 3336.

Additive manufacturing (AM) of metals provides great flexibility in manufacturing parts with complex geometrical shapes and is fast becoming an attractive option for the fabrication of high-valued metal components in aerospace, oil & gas, and biomedical industries. The rapid heating and cooling during AM fabrication, which by nature is a highly nonequilibrium process, often leads to significant microstructural heterogeneity uncommon to wrought and cast alloys. Such heterogeneity creates tremendous challenge in the qualification and eventual certification of AM metal parts for many applications.

Using a combination of in situ synchrotron-based X-ray scattering and diffraction methods, ex situ electron microscopy, atom-probe tomography, and thermokinetic and thermodynamic modelling, we have focused on the development of post-build heat treatment protocols for AM alloys. Our established protocols recover the designed phase composition of two types of widely used commercial AM alloys, a major step towards their part certification. Specifically, our work on AM nickel-based superalloy Inconel 625 demonstrates the importance of understanding the effect of elemental microsegregation, a ubiquitous phenomenon in AM alloys resulting from rapid solidification, on the structure and microstructure evolution during post-build heat treatments [1]. Our simulation-constructed and experiment-validated time-temperature-transformation diagram clearly demonstrates the acceleration (by a factor of 100 – 1000) of formation kinetics of a phase deleterious to the fatigue performance of this alloy [2, 3]. Our work on nitrogen-atomized 17-4 stainless steel shows that the starting powder chemistry and compositional partition during solidification results in the as-fabricated 17-4 being fully austenitic, as opposed to being fully martensitic as designed. Our three-step heat treatment protocol successfully recovers the martensitic structure of parts fabricated using nitrogen-atomized 17-4 powders [4]. We also determined the optimal ageing heat treatment to yield optimal strength of this precipitation-hardening alloy.

Our work points to a common and important theme that post-build heat treatment is critical for producing AM alloys with predictable and reproducible microstructures and hence materials properties. The emphasis of proper post-build heat treatment cannot be overstated for the certification of many AM alloys. We also emphasize that rigorous and in situ bulk structure and microstructure measurements only available at synchrotrons are essential for modelers to validate AM simulations for the advancement of AM technologies [5].

References:

[1] Zhang, F., Levine, L. E., Allen, A. J., Stoudt, M. R., Lindwall, G., Lass, E. A., Williams, M. E., Idell, Y. & Campbell, C. E. (2018). Acta Materialia 152, 200-214.

[2] Stoudt, M. R., Lass, E., Ng, D. S., Williams, M. E., Zhang, F., Campbell, C. E., Lindwall, G. & Levine, L. E. (2018). Metallurgical and Materials Transactions A 49, 3028-3037.

[3] Lindwall, G., Campbell, C., Lass, E., Zhang, F., Stoudt, M. R., Allen, A. J. & Levine, L. E. (2019). Metallurgical and Materials Transactions A 50, 457-467.

[4] Lass, E. A., Zhang, F. & Campbell, C. E. (2020). Metallurgical and Materials Transactions A, 1-15.

[5] Zhang, F., Levine, L. E., Allen, A. J., Young, S. W., Williams, M. E., Stoudt, M. R., Moon, K.-W., Heigel, J. C. & Ilavsky, J. (2019). Integrating Materials and Manufacturing Innovation 8, 362-377

Acknowledgement:

Portions of this research were performed on beamline 9-ID-C, 11-ID-B, and 11-BM at the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Nanofluids, i. e. liquids containing dispersed nanoparticles, are gaining increasing interest since the first use of this designation by Choi in 1995 [1]. The primary application for heat transfer as a thermally conductive fluid for cooling is nowadays expanding to sensors, lubricants, magnetic sealing or solar energy collectors. The unique properties of nanofluids arise from the synergy between nanoparticles and the surrounding medium. Our study concerns Ag and Au nanoparticles which belong to plasmonic nanoparticles with the localized particles plasmon resonance (LPPR) in the region of visible light which makes them and their colloidal suspensions attractive for optical applications.

There are numerous preparation methods of nanofluids, among them the very straightforward and solvent-free is magnetron sputtering of metals on the surface of vacuum-compatible liquids (oils, ionic liquids, and polymers). In this method nanoparticles are formed at the vacuum-liquid interface [2]. In our work, the nanoparticle synthesis takes place in the gas phase prior to their landing onto the liquid. Silver and gold nanoparticles were prepared using a magnetron-based gas aggregation cluster source and subsequently deposited into liquid polyethylene glycol (PEG).

The main aim of our study is to determine the stability of Ag and Au nanoparticle dispersions in PEG and to understand the post-deposition processes inside the nanofluids comprising nanoparticles prepared by aggregation from the gas phase. Solutions with different mass concentration of nanoparticles were prepared by controlling the deposition time reaching tens of mg/ml, a value typical for commercially-available Ag colloidal solutions. To investigate the size distributions and interactions between nanoparticles inside the colloidal suspensions the small angle x-ray scattering (SAXS) was used. We performed SAXS measurements repeatedly during six months to determine the suspension stability. The x-ray diffraction proved the crystalline nature of nanoparticles and also the changes in the amount of material dispersed in the suspension. The optical properties of individual suspensions were analyzed by UV-Vis spectroscopy. TEM and SEM measurements of nanoparticles separated from the suspensions were performed to validate the results obtained by the scattering methods.

Prepared Au nanoparticles have bimodal size distribution with mean sizes 13 nm and 40 nm and the corresponding absorption peak associated to the LPPR is observed around 550 nm in the UV-Vis spectrum. In the case of Ag nanoparticles dispersion, UV-Vis spectroscopy shows the maximum corresponding to the LPPR of individual separated nanoparticles around 410 nm and another maximum at larger wavelengths corresponding to nanoparticles aggregates for freshly prepared samples. This observation was further confirmed by SAXS, the mean size of single nanoparticles is around 10 nm and the nanoparticles interact through the hard-sphere interaction. The hard-sphere volume fraction however decreases in time and after two months is not detectable anymore. The resultant suspension exhibited characteristic plasmonic colour in the yellow/orange range and is expected to be stable over extended periods due to constrained mobility of PEG’s macromolecular chains.

[1] Choi, S. U. S., & Eastman, J. A. (1995). American Society of Mechanical Engineers, 231 (March), 99–105.

[2] Wender, H., Gonçalves, R. V., Feil, A. F., Migowski, P., Poletto, F. S., Pohlmann, A. R., Dupont, J., & Teixeira, S. R. (2011). Journal of Physical Chemistry C, 115(33), 16362–16367.

This study was financed by the Grant Agency of Charles University (grant 1546119), by the Czech Science Foundation (grant GACR 21-12828S) and by ERDF in the frame of the project NanoCent - Nanomaterials Centre for Advanced Applications (Project No. CZ.02.1.01/0.0/0.0/15_003/0000485).

The Pb(Zn1/3Nb2/3)O3-4.5PbTiO3 (PZN-4.5PT) single crystals showed very large ferroelectric and piezoelectric properties compared to traditional ferroelectric ceramics (BaTiO3 and PZT) used presently as active material in medical imaging, detection and sonars. However, despite these excellent properties, the greatest difficulty to use PZN-4.5PT single crystals on electronic devices is to achieve them in thin layers form because of their incongruent melting property. To overcome this difficulty, we deposit them as thin layers by dispersing their nanoparticles in a gel containing a matrix that can maintain at least their bulk properties. After this size reduction at nanoscale and the annealing process following the deposition, changes and structural transformations would occur. We fabricate with success thin films by dispersing these nanoparticles in a gel. The materials show some agglomeration at the surface of the silicon substrate films (from SEM images) and non-identified hexagonal microcrystals, which could be at the origin of their excellent properties.

In this paper we use the combined USAXS/SAXS/WAXS instrument at 9ID beamline at APS-ANL for in situ characterization of undoped and 1% Mn doped PZN-4.5PT inorganic perovskite nanoparticles thin films deposited on nanostructured silicon to understand the phases transitions and determine the observed hexagonal microcrystals structure. It revealed a hexagonal structure of the nanoparticles thin films, which could be explained by the new phase that can be assigned to the Pb3(PO4)2 based component. The peak at 31° indicates the presence of the rhombohedral phase perovskites assigned to the nanoparticles. XRD spectra, Raman and EDX mapping are compared to the USAXS, SAXS and WAXS results. WAXS characterization permitted to identify three phase transitions during thermal annealing confirming dielectric permittivity temperature phases transitions.

Complex liquid mixtures are the foundation of industrial products from personal care products to biotherapeutics to specialty chemicals. While small- and wide-angle reciprocal space methods (SANS, SAXS, WAXS) are workhorse techniques for characterizing model formulations, the large number of components (10-100) in many real products often prevents rational mapping between component fractions, structure, and product stability. To enable rational design of these materials, we must leverage theory, simulation, multimodal characterization and machine learning (ML) tools to greatly reduce the expense of exploring the stability boundaries of a particular, desirable phase. Applying ML tools to scattering experiments requires a platform capable of autonomously synthesizing and characterizing samples with varying composition and chemistry. While there are numerous examples of robots which perform specific user facility operations, these systems tend to be bespoke and non-adaptable to new tasks. We have developed a highly adaptable platform that can be programmed to autonomously prepare and characterize liquid-formulations using neutron and X-ray scattering in addition to offline techniques such as optical imaging, UV/vis/NIR, viscometry, etc. Here we will highlight the design of the platform and our latest results in autonomous stability mapping of model formulations from personal care, biopharmaceutical, and alternative energy partner companies.