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Instruments / Technical Area	Publication Details	Published
I22-Small angle scattering & Diffraction	An organic crystalline state in ageing atmospheric aerosol proxies: spatially resolved structural changes in levitated fatty acid particles Adam Milsom , Adam M. Squires , Jacob A. Boswell , Nicholas J. Terrill , Andrew D. Ward , Christian Pfrang Atmospheric Chemistry And Physics 21, 15003 - 15021 DOI: 10.5194/acp-21-15003-2021 Diamond Proposal Number(s): [20541, 21663] Open Access Show Abstract ▼ Abstract: Organic aerosols are key components of the Earth's atmospheric system. The phase state of organic aerosols is known to be a significant factor in determining aerosol reactivity, water uptake and atmospheric lifetime – with wide implications for cloud formation, climate, air quality and human health. Unsaturated fatty acids contribute to urban cooking emissions and sea spray aerosols. These compounds, exemplified by oleic acid and its sodium salt, are surface-active and have been shown to self-assemble into a variety of liquid-crystalline phases upon addition of water. Here we observe a crystalline acid–soap complex in acoustically levitated oleic acid–sodium oleate particles. We developed a synchrotron-based simultaneous small-angle and wide-angle X-ray scattering (SAXS and WAXS)–Raman microscopy system to probe physical and chemical changes in the proxy during exposure to humidity and the atmospheric oxidant ozone. We present a spatially resolved structural picture of a levitated particle during humidification, revealing a phase gradient consisting of a disordered liquid crystalline shell and crystalline core. Ozonolysis is significantly slower in the crystalline phase compared with the liquid phase, and a significant portion (34 ± 8 %) of unreacted material remains after extensive oxidation. We present experimental evidence of inert surface layer formation during ozonolysis, taking advantage of spatially resolved simultaneous SAXS–WAXS experiments. These observations suggest that atmospheric lifetimes of surface-active organic species in aerosols are highly phase-dependent, potentially impacting climate, urban air quality and long-range transport of pollutants such as polycyclic aromatic hydrocarbons (PAHs).	Oct 2021
I22-Small angle scattering & Diffraction	The hygroscopicity and reactivity of fatty acid atmospheric aerosol proxies are affected by nanostructure Adam Milsom , Adam Squires , Nicholas Terrill , Andrew Ward , Christian Pfrang EGU General Assembly 2021 DOI: 10.5194/egusphere-egu21-7326 Open Access Show Abstract ▼ Abstract: Atmospheric aerosol hygroscopicity and reactivity play a significant role in determining aerosol fate, and are affected by composition and other physical properties. Organic aerosol emissions contain fatty acids, along with sugars such as fructose. As surfactants, fatty acids organise into a range of nanostructures (3-D molecular arrangements), dependent on water content and mixture composition. In this study, we were able to demonstrate (and quantify) that the chemical reactivity of this proxy is dependent on its 3-D molecular arrangement. Furthermore, we have determined the effect of each observed nanostructure on hygroscopicity by measuring the swelling of these nanostructures as a function of relative humidity. We did this by coating capillaries with a fatty acid/sugar as a mixture for an urban aerosol, and following structural changes with simultaneous Small-Angle X-ray Scattering (SAXS) and Raman microscopy, at a synchrotron X-ray source. SAXS measured the nano-structural parameters required to follow both the reaction kinetics (ozonolysis) and hygroscopic swelling of each nanostructure. Raman microscopy provided complementary kinetic information and supported these findings. We found that the molecular arrangement of surfactant material has an impact on both the chemical kinetics and hygroscopicity. This has implications for the persistence of particulate matter in the urban environment and surfactant material in the atmosphere.	Mar 2021
I22-Small angle scattering & Diffraction	The persistence of a proxy for cooking emissions in megacities: a kinetic study of the ozonolysis of self-assembled films by simultaneous Small & Wide Angle X-ray Scattering (SAXS/WAXS) and Raman microscopy Adam Milsom , Adam M. Squires , Ben Woden , Nicholas J. Terrill , Andrew D. Ward , Christian Pfrang Faraday Discussions DOI: 10.1039/D0FD00088D Diamond Proposal Number(s): [21663, 23096] Open Access Show Abstract ▼ Abstract: Cooking emissions account for a significant proportion of the organic aerosol emitted into the urban environment and high pollution events have been linked to an increased organic content on urban particulate matter surfaces. We present a kinetic study on surface coatings of self-assembled (semi-solid) oleic acid-sodium oleate cooking aerosol proxies undergoing ozonolysis. We found a clear film thickness-dependent kinetic behaviour and measured the effect of the organic phase on the kinetics for this system. In addition to the thickness-dependent kinetics, we show that significant fractions of unreacted proxy remain at the end of extensive ozone exposure and that this effect scales approximately linearly with film thickness, suggesting that a late-stage inert reaction product may form to inhibit reaction progress – effectively building up an inert crust. We determine this by using a range of simultaneous analytical techniques; most notably Small-Angle X-ray Scattering (SAXS) has been used for the first time to measure reaction kinetics of films of a wide range of thicknesses from ca. 0.59 to 73 µm with films < 10 µm thick being of potential atmospheric relevance. These observations have implications for the evolution of particulate matter in the urban environment, potentially extending the atmospheric lifetimes of harmful aerosol components and affecting the local urban air quality and climate.	Sep 2020
E02-JEM ARM 300CF I22-Small angle scattering & Diffraction	3D nanostructured palladium with single diamond architecture for enhanced catalytic activity Matthew Burton , Anand Selvam , Jake Lawrie-Ashton , Adam M. Squires , Nicholas Terrill , Iris Nandhakumar Acs Applied Materials & Interfaces DOI: 10.1021/acsami.8b13230 Diamond Proposal Number(s): [14925, 10330, 16964] Show Abstract ▼ Abstract: Fuel cells are a key new green technology that have applications in both transport and portable power generation. Carbon supported platinum (Pt) is used as an anode and cathode electrocatalyst in low-temperature fuel cells fuelled with hydrogen or low molecular weight alcohols. The cost of Pt and the limited world supply are significant barriers to the widespread use of these types of fuel cells. Compara-tively palladium has a three times higher abundance in the Earth’s crust. Here a facile, low temperature and scalable synthetic route to-wards 3D nanostructured palladium (Pd) employing electrochemical templating from inverse lyotropic lipid phases is presented. The obtained single diamond morphology Pd nanostructures exhibited excellent catalytic activity and stability towards methanol, ethanol and glycerol oxidation compared to commercial Pd black and the nanostructure was verified by small-angle X-ray scattering (SAXS), scanning tunneling electron microscopy (STEM) as well as by cyclic voltammetry (CV).	Oct 2018
B21-High Throughput SAXS	Complex three-dimensional self-assembly in proxies for atmospheric aerosols C. Pfrang , K. Rastogi , Edna Cabrera-martinez , A. M. Seddon , C. Dicko , A. Labrador , T. S. Plivelic , N. Cowieson , A. M. Squires Nature Communications 8 DOI: 10.1038/s41467-017-01918-1 Diamond Proposal Number(s): [16578] Open Access Show Abstract ▼ Abstract: Aerosols are significant to the Earth’s climate, with nearly all atmospheric aerosols containing organic compounds that often contain both hydrophilic and hydrophobic parts. However, the nature of how these compounds are arranged within an aerosol droplet remains unknown. Here we demonstrate that fatty acids in proxies for atmospheric aerosols self-assemble into highly ordered three-dimensional nanostructures that may have implications for environmentally important processes. Acoustically trapped droplets of oleic acid/sodium oleate mixtures in sodium chloride solution are analysed by simultaneous synchrotron small-angle X-ray scattering and Raman spectroscopy in a controlled gas-phase environment. We demonstrate that the droplets contained crystal-like lyotropic phases including hexagonal and cubic close-packed arrangements of spherical and cylindrical micelles, and stacks of bilayers, whose structures responded to atmospherically relevant humidity changes and chemical reactions. Further experiments show that self-assembly reduces the rate of the reaction of the fatty acid with ozone, and that lyotropic-phase formation also occurs in more complex mixtures more closely resembling compositions of atmospheric aerosols. We suggest that lyotropic-phase formation likely occurs in the atmosphere, with potential implications for radiative forcing, residence times and other aerosol characteristics.	Nov 2017
I22-Small angle scattering & Diffraction	3D semiconducting nanostructures via inverse lipid cubic phases M. R. Burton , C. Lei , P. A. Staniec , N. J. Terrill , A. M. Squires , N. M. White , Iris S. Nandhakumar Scientific Reports 7 DOI: 10.1038/s41598-017-06895-5 Diamond Proposal Number(s): [14925, 10330] Open Access Show Abstract ▼ Abstract: Well-ordered and highly interconnected 3D semiconducting nanostructures of bismuth sulphide were prepared from inverse cubic lipid mesophases. This route offers significant advantages in terms of mild conditions, ease of use and electrode architecture over other routes to nanomaterials synthesis for device applications. The resulting 3D bicontinous nanowire network films exhibited a single diamond topology of symmetry Fd3m (Q227) which was verified by Small angle X-ray scattering (SAXS) and Transmission electron microscopy (TEM) and holds great promise for potential applications in optoelectronics, photovoltaics and thermoelectrics.	Jul 2017
I07-Surface & interface diffraction	Watching Mesoporous Metal Films Grow During Templated Electrodeposition with In Situ SAXS Samuel J. Richardson , Matthew R. Burton , Xiatong Luo , Paul A. Staniec , Iris S. Nandhakumar , Nick J. Terrill , Joanne M. Elliott , Adam M. Squires Nanoscale DOI: 10.1039/C7NR03321D Diamond Proposal Number(s): [10330] Show Abstract ▼ Abstract: In this paper, we monitor real-time growth of mesoporous platinum during electrodeposition using small-angle X-ray scattering (SAXS). Previously we have demonstrated that platinum films featuring ‘single diamond’ (Fd3m) morphology can be produced from ‘double diamond’ (Pn3m) lipid cubic phase templates; the difference in symmetry provides additional scattering signals unique to the metal. Taking advantage of this, we present simultaneous in situ SAXS / electrochemical measurement as the platinum nanostructures grow within the lipid template. This measurement allows us to correlate the nanostructure appearance with the deposition current density and to monitor the evolution of orientational and lateral ordering of the lipid and platinum during deposition and after template removal. In other periodic metal nanomaterials deposited within any of the normal topology liquid crystal, mesoporous silica or block copolymer templates previously published, the template and emerging metal have the same symmetry, so such a study has not previously been possible.	Jun 2017
I07-Surface & interface diffraction I22-Small angle scattering & Diffraction	A novel route to nanostructured bismuth telluride films by electrodeposition M. R. Burton , S. J. Richardson , P. A. Staniec , N. J. Terrill , J. M. Elliott , A. M. Squires , N. M. White , Iris S. Nandhakumar Electrochemistry Communications 76, 71 - 74 DOI: 10.1016/j.elecom.2017.02.004 Diamond Proposal Number(s): [9678, 1156, 14925, 10330] Show Abstract ▼ Abstract: We report a novel route to the fabrication of 3D nanostructured stoichiometric bismuth telluride (Bi2Te3) films by electrodeposition through inverse lipid cubic phases as evidenced by Small-angle X-ray Scattering (SAXS) and Helium Ion Microscopy (HIM). The nanostructured Bi2Te3 films were composed of interconnected nanowires with diameters of 60–150 Å.	Mar 2017
B21-High Throughput SAXS	Modification of β-sheet forming peptide hydrophobic face: effect on self-assembly and gelation Mohamed Elsawy , Andrew M. Smith , Nigel Hodson , Adam Squires , Aline Fiona Miller , Alberto Saiani Langmuir DOI: 10.1021/acs.langmuir.5b03841 Diamond Proposal Number(s): [12950] Open Access Show Abstract ▼ Abstract: Beta-sheet forming peptides have attracted significant interest for the design of hydrogels for biomedical applications. One of the main challenges is the control and understanding of the correlations between peptide molecular structure, the morphology, and topology of the fiber and network formed as well as the macroscopic properties of the hydrogel obtained. In this work, we have investigated the effect that functionalizing these peptides through their hydrophobic face has on their self-assembly and gelation. Our results show that the modification of the hydrophobic face results in a partial loss of the extended -sheet conformation of the peptide and a significant change in fiber morphology from straight to kinked. As a consequence the ability of these fibers to associate along their length and form large bundles is reduced leading. These structural changes (fiber structure and network topology) significantly affect the mechanical properties of the hydrogels (shear modulus and elasticity).	Apr 2016
I07-Surface & interface diffraction	Aligned platinum nanowire networks from surface-oriented lipid cubic phase templates S. Richardson , M. R. Burton , P. A. Staniec , I. S. Nandhakumar , N. J. Terrill , J. M. Elliott , A. M. Squires Nanoscale 8, 2850 - 2856 DOI: 10.1039/C5NR06691C PMID: 26763739 Diamond Proposal Number(s): [10330] Show Abstract ▼ Abstract: Mesoporous metal structures featuring a bicontinuous cubic morphology have a wide range of potential applications and novel opto-electronic properties, often orientation-dependent. We describe the production of nanostructured metal films 1–2 microns thick featuring 3D-periodic ‘single diamond’ morphology that show high out-of-plane alignment, with the (111) plane oriented parallel to the substrate. These are produced by electrodeposition of platinum through a lipid cubic phase (QII) template. Further investigation into the mechanism for the orientation revealed the surprising result that the QII template, which is tens of microns thick, is polydomain with no overall orientation. When thicker platinum films are grown, they also show increased orientational disorder. These results suggest that polydomain QII samples display a region of uniaxial orientation at the lipid/substrate interface up to approximately 2.8 ± 0.3 μm away from the solid surface. Our approach gives previously unavailable information on the arrangement of cubic phases at solid interfaces, which is important for many applications of QII phases. Most significantly, we have produced a previously unreported class of oriented nanomaterial, with potential applications including metamaterials and lithographic masks.	Jan 2016

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