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Instruments / Technical Area	Publication Details	Published
	Wavelength frame multiplication for reflectometry at long-pulse neutron sources Oliver Löhmann , Luca Silvi , Peter M. Kadletz , Neil Vaytet , Owen Arnold , Matthew D. Jones , Jonas Nilsson , Michael Hart , Tobias Richter , Regine Von Klitzing , Andrew J. Jackson , Thomas Arnold , Robin Woracek Review Of Scientific Instruments 91 DOI: 10.1063/5.0014207 Open Access Show Abstract ▼ Abstract: The European Spallation Source (ESS), which is under construction in Lund (Sweden), will be the next leading neutron facility with an unprecedented brilliance and novel long-pulse time structure. A long-pulse source not only provides a high time-average flux but also opens the possibility to tune the resolution by using pulse shaping choppers. Thus, an instrument can readily be operated in either a high flux or a high resolution mode. Several of the shorter instruments at the ESS will employ Wavelength Frame Multiplication (WFM) in order to enable a sufficient resolution while offering a continuous and broad wavelength range. A test beamline was operated until the end of 2019 at the research reactor in Berlin to test components and methods, including WFM, in order to prepare the new facility for the operation of neutron instruments and successful first science. We herein demonstrate the implementation of WFM for reflectometry. By selecting a short pulse mode under the same geometrical configuration, we compare and discuss the results for two reference samples. The reported experiments not only serve to prove the reliability of the WFM approach but also, for the first time, demonstrate the full instrument control, data acquisition and data reduction chain that will be implemented at the ESS.	Dec 2020
I07-Surface & interface diffraction	Bayesian determination of the effect of a deep eutectic solvent on the structure of lipid monolayers Andrew R. Mccluskey , Adrian Sanchez-Fernandez , Karen J. Edler , Stephen C. Parker , Andrew J. Jackson , Richard A. Campbell , Thomas Arnold Physical Chemistry Chemical Physics 114 DOI: 10.1039/C9CP00203K Diamond Proposal Number(s): [10546] Open Access Show Abstract ▼ Abstract: In this work, we present the first example of the self-assembly of phospholipid monolayers at the interface between air and an ionic solvent. Deep eutectic solvents are a novel class of environmentally friendly, non-aqueous, room temperature liquids with tunable properties, that have wide-ranging potential applications and are capable of promoting the self-assembly of surfactant molecules. We use a chemically-consistent Bayesian modelling of X-ray and neutron reflectometry measurements to show that these monolayers broadly behave as they do on water. This method allows for the monolayer structure to be determined, alongside the molecular volumes of the individual monolayer components, without the need for water-specific constraints to be introduced. Furthermore, using this method we are able to better understand the correlations present between parameters in the analytical model. This example of a non-aqueous phospholipid monolayer has important implications for the potential uses of these solvents and for our understanding of how biomolecules behave in the absence of water.	Feb 2019
I07-Surface & interface diffraction	Self-assembly and surface behaviour of pure and mixed zwitterionic amphiphiles in a deep eutectic solvent Adrian Sanchez-Fernandez , Georgina L. Moody Moody , Lloyd C. Murfin , Thomas Arnold , Andrew J. Jackson , Stephen M. King , Simon E. Lewis , Karen J. Edler Soft Matter DOI: 10.1039/C8SM00755A Diamond Proposal Number(s): [15584] Open Access Show Abstract ▼ Abstract: Recent investigations have shown that deep eutectic solvents provide a suitable environment for self-organisation of biomolecules, in particular phospholipids and proteins. However, the solvation of complex lyophilic moieties by deep eutectic solvents still remains unclear. Here we explore the behaviour of zwitterionic surfactants in choline chloride:glycerol eutectic mixture. Dodecyl-2-(trimethylammonio)ethylphosphate and N-alkyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (alkyl=dodecyl, tetradecyl) surfactants were investigated by means of surface tension, X-Ray reflectivity and small-angle neutron scattering. These surfactants were found to remain surface active and form globular micelles in deep eutectic solvents. Still, the surface behaviour of these species was found to differ depending on the headgroup and tail structure. The morphology of the micelles also slightly varies between surfactants, demonstrating differences in the packing of individual monomers. The characteristics of mixtures of the dodecyl surfactants is also reported, showing a deviation from ideal mixing associated with attractive interactions between sulfobetaine and phosphocholine headgroups. Such non-ideality results in variation of the surface behaviour and self-assembly of these surfactant mixtures. The results presented here will potentially lead to the development of new alternatives for drug-delivery, protein solubilisation and biosensing through a better fundamental understanding of the behaviour of zwitterionic surfactants in deep eutectic solvents.	Jun 2018
	Surfactant-solvent interaction effects on the micellization of cationic surfactants in a carboxylic acid-based deep eutectic solvent Adrian Sanchez-Fernandez , Oliver S. Hammond , Andrew J. Jackson , Thomas Arnold , James Doutch , Karen J. Edler Langmuir DOI: 10.1021/acs.langmuir.7b03254 Open Access Show Abstract ▼ Abstract: Deep eutectic solvents have been demonstrated to support amphiphile self-assembly, providing potential alternatives as structure directing agents in the synthesis of nanostructures, and drug delivery. Here we have expanded on this recent research to investigate the self-assembly of alkyltrimethylammonium bromide surfactants in choline chloride:malonic acid deep eutectic solvent and mixtures of the solvent with water. Surface tension and small-angle neutron scattering were used to determine the behavior of the amphiphiles. Surfactants were found to remain active in the solvent and surface tension measurements revealed changes in the behavior of the surfactants with different levels of hydration. Small-angle neutron scattering shows that in this solvent the micelle shape depends on the surfactant chain length, varying from globular micelles (aspect ratio ~2) for short chain surfactants to elongated micelles (aspect ratio ~14) for long chain surfactants even at low surfactant concentration. We suggest that the formation of elongated micelles can be explained through the interaction of the solvent with the surfactant headgroup, since ion-ion interactions between surfactant headgroups and solvent may modify the morphology of the micelles. The presence of water in the deep eutectic solvents promotes an increase in the charge density at the micelle interface and therefore the formation of less elongated, globular micelles.	Nov 2017
	Resilience of malic acid natural deep eutectic solvent nanostructure to solidification and hydration Oliver S. Hammond , Daniel Timothy Bowron , Andrew J. Jackson , Thomas Arnold , Adrian Sanchez Fernandez , Nikolaos Tsapatsaris , Victoria Garcia Sakai , Karen J. Edler The Journal Of Physical Chemistry B DOI: 10.1021/acs.jpcb.7b05454 Open Access Show Abstract ▼ Abstract: Little is presently known about the unique nanostructure of Deep Eutectic Solvents (DES). The order of the liquid-solid phase transition is contended and whether DES-water mixtures are merely aqueous solutions, or have properties dominated by the eutectic pair, is unclear. Here, we unambiguously show the structure of choline chloride-malic acid (malicine) as a liquid, and also in solid and hydrated forms, using neutron total scattering on D/H isotope-substituted samples, and quasi-elastic neutron scattering (QENS). Data were refined using Empirical Potential Structure Refinement. We show evidence for a stoichiometric complex ion cluster in the disordered liquid, with strong choline-chloride bonding and a hydrogen bond donor (HBD) contribution. The 1:1 eutectic stoichiometry makes these ionic domains more well-defined, with less HBD clustering than seen previously for reline. There is minimal structural difference for the solidified material, demonstrating that this DES solidification is a glass transition rather than a first order phase change. QENS data support this by showing a gradual change in solvent dynamics rather than a step change. The DES structure is mostly retained upon hydration, with water acting both as a secondary smaller HBD at closer range to choline than malic acid, and forming transient wormlike aggregates. This new understanding of DES structure will aid understanding of the properties of these novel green solvents on the molecular length scale in chemical processes, as well as giving an insight into the apparent role of natural DESs in plant physiology.	Jul 2017
I07-Surface & interface diffraction	Micellisation of alkyltrimethylammonium bromide surfactants in choline chloride:glycerol deep eutectic solvent Adrian Sanchez Fernandez , Thomas Arnold , Andrew J. Jackson , Sian L. Fussell , Richard K Heenan , Richard Campbell , Karen J. Edler Physical Chemistry Chemical Physics DOI: 10.1039/C6CP06053F Diamond Proposal Number(s): [10546] Open Access Show Abstract ▼ Abstract: Deep eutectic solvents have shown the ability to promote the self-assembly of surfactants in solution. However, some differences have been found compared with self assembly in pure water and other polar organic solvents. The behaviour of alkyltrimethylammonium bromides in choline chloride:glycerol deep eutectic solvent has been studied by means of surface tension, X-Ray and neutron reflectivity and small-angle neutron scattering. The surfactants were found to remain surface active and showed comparable critical micelle concentrations to the same surfactants in water. Our scattering studies demonstrate that these surfactants form globular micelles with ellipsoidal shape in solution. The size, shape and aggregation number of the aggregates were found to vary with the chain length of the surfactant. Specific solvent-headgroup interactions were not found in this system, unlike those we have previously postulated for anionic surfactants in choline chloride deep eutectic solvents.	Nov 2016
I22-Small angle scattering & Diffraction	Micelle structure in a deep eutectic solvent: a small-angle scattering stud Adrian Sanchez Fernandez , Karen J. Edler , Tom Arnold , Richard K Heenan , Lionel Porcar , Nicholas Terrill , Ann Terry , Andrew Jackson Physical Chemistry Chemical Physics DOI: 10.1039/C6CP01757F Diamond Proposal Number(s): [11392] Open Access Show Abstract ▼ Abstract: In recent years many studies into green solvents have been undertaken and Deep Eutectic Solvents (DES) have emerged as sustainable and green alternatives to conventional solvents, since they can be formed from cheap, non-toxic organic precursors. In this study we examine amphiphile behaviour in these novel media to test our understanding of amphiphile self-assembly within environments that have an intermediate polarity between polar and non-polar extremes. We have built on our recently published results to present a more detailed structural characterisation of micelles of sodium dodecylsulfate (SDS) within the eutectic mixture of choline chloride and urea. Here we show that SDS adopts an unusual cylindrical aggregate morphology, unlike that seen in water and other polar solvents. A new morphology transition to shorter aggregates was found with increasing concentration and correlated with the specific interaction of choline ions with the surfactant headgroups. The self-assembly of SDS in this solvent was also investigated in the presence of water; which promotes the formation of shorter aggregates.	Apr 2016
I22-Small angle scattering & Diffraction	Combined pressure and temperature denaturation of ribonuclease A produces alternate denatured states Timothy M. Ryan , Yun Xun , Nathan P. Cowieson , Jitendra P. Mata , Andrew Jackson , Brian R. Pauw , Andrew Smith , Nigel Kirby , Duncan Mcgillivray Biochemical And Biophysical Research Communications DOI: 10.1016/j.bbrc.2016.03.135 Show Abstract ▼ Abstract: Protein folding, unfolding and misfolding have become critically important to a range of health and industry applications. Increasing high temperature and high pressure are used to control and speed up reactions. A number of studies have indicated that these parameters can have a large ffect on protein structure and function. Here we describe the additive effects of these parameters on the small angle scattering behavior of ribonuclease A. We find that alternate unfolded structures can be obtained with combined high pressure and temperature treatment of the protein.	Mar 2016
I07-Surface & interface diffraction	Surfactant behavior of sodium dodecylsulfate in deep eutectic solvent choline chloride/urea T Arnold , A Jackson , A. Sanchez-Fernandez , D. Magnone , A. E. Terry , K. J. Edler Langmuir 31 (47) DOI: 10.1021/acs.langmuir.5b02596 PMID: 26540438 Diamond Proposal Number(s): [9748] Open Access Show Abstract ▼ Abstract: Deep eutectic solvents (DES) resemble ionic liquids but are formed from an ionic mixture instead of being a single ionic compound. Here we present some results that demonstrate that surfactant sodium dodecyl sulfate (SDS) remains surface-active and shows self-assembly phenomena in the most commonly studied DES, choline chloride/urea. X-ray reflectivity (XRR) and small angle neutron scattering (SANS) suggest that the behavior is significantly different from that in water. Our SANS data supports our determination of the critical micelle concentration using surface-tension measurements and suggests that the micelles formed in DES do not have the same shape and size as those seen in water. Reflectivity measurements have also demonstrated that the surfactants remain surface-active below this concentration.	Nov 2015
I22-Small angle scattering & Diffraction	Learning about SANS instruments and data reduction from round robin measurements on samples of polystyrene latex Adrian R. Rennie , Maja S. Hellsing , Kathleen Wood , Elliot P. Gilbert , Lionel Porcar , Ralf Schweins , Charles D. Dewhurst , Peter Lindner , Richard K. Heenan , Sarah Rogers , Paul D. Butler , Jeffery R. Krzywon , Ron E. Ghosh , Andrew J. Jackson , Marc Malfois Journal Of Applied Crystallography 46 (5), 1289 - 1297 DOI: 10.1107/S0021889813019468 Show Abstract ▼ Abstract: Measurements of a well-characterised ‘standard’ sample can verify the performance of an instrument. Typically, small-angle neutron scattering instruments are used to investigate a wide range of samples and may often be used in a number of configurations. Appropriate ‘standard’ samples are useful to test different aspects of the performance of hardware as well as that of the data reduction and analysis software. Measurements on a number of instruments with different intrinsic characteristics and designs in a round robin can not only better characterise the performance for a wider range of conditions but also, perhaps more importantly, reveal the limits of the current state of the art of small-angle scattering. The exercise, followed by detailed analysis, tests the limits of current understanding as well as uncovers often forgotten assumptions, simplifications and approximations that underpin the current practice of the technique. This paper describes measurements of polystyrene latex, radius 720 Å with a number of instruments. Scattering from monodisperse, uniform spherical particles is simple to calculate and displays sharp minima. Such data test the calibrations of intensity, wavelength and resolution as well as the detector response. Smoothing due to resolution, multiple scattering and polydispersity has been determined. Sources of uncertainty are often related to systematic deviations and calibrations rather than random counting errors. The study has prompted 2 development of software to treat modest multiple scattering and to better model the instrument resolution. These measurements also allow checks of data reduction algorithms and have identified how they can be improved. The reproducibility and the reliability of instruments and the accuracy of parameters derived from the data are described.	Oct 2013

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