| 1. |
- Adlmann, Franz Alois
(författare)
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Opportunities and challenges of surface scattering at next generation neutron sources
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Complex fluids and soft matter are ubiquitously found in the world and all contacts in life are made over surfaces. To describe the mechanical behavior of such substances, rheological methods are used. Flow instabilities are a big challenge in rheology since they will be reflected in the macroscopic variables probed, like e. g. the viscosity. Many such discontinuities may actually originate at the surface. Investigating the properties of liquids in contact with the surface under mechanical load is the main course of the thesis. Neutron reflectometry and GISANS are perfect tools in this context to access the solid liquid interfaces, since they can penetrate many engineering materials and show a comparably large scattering potential at deuterated samples. In this thesis shear was applied on a model solution and neutron scattering techniques were used to investigate the structure under load. The focus was set on the development of the measurement methods themselves to enable new scientific insights in the future. First, by stroboscopic measurements the flux limitations are overcome for oscillatory rheology. By reintegration in the post processing it is shown that kinetic measurements with neutrons are possible with a time resolution below one millisecond. Second, the transformation of grazing incidence data from the laboratory system into q-space is strongly non-linear resulting in a need for re-binning. In this thesis a universal tool has been developed for this purpose. Finally, there is an ongoing discussion on depth sensitive neutron scattering experiments from solid-liquid boundaries. By using emission densities we show that such experiments face severe limitations due to the low absorption cross section of the neutron.
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| 2. |
- Al Jebali, Ramsey, et al.
(författare)
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Recent Developments SoNDe High-Flux Detector Project
- 2018
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Ingår i: Recent Developments SoNDe High-Flux Detector Project.
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Konferensbidrag (refereegranskat)abstract
- New high-flux and high-brilliance neutron sources demand a higher count-rate capability in neutron detectors. In order to achieve that goal, the Solid-State Neutron Detector (SoNDe) project is developing a scintillation-based neutron detector. It will be capable of fully exploiting the available flux at small-angle neutron scattering (SANS) instruments at high brilliance sources, such as SKADI at the European Spallation Source (ESS). The read-out of the scintillator is based on a pixelized multi-anode PMT (MaPMT), where each pixel is treated separately. In addition to enabling higher achievable count-rates, one of the design goals was to develop a modular and scalable solution that can also be used in other instruments or even contexts, such as for laboratory setups. This has been achieved by combining the complete read-out electronics along with the MaPMT into modules that can be controlled and read-out individually via a network without additional any infrastructure. An overview of the present state of development and current test results is presented, highlighting the results of previously published project reports.
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| 3. |
- Brett, Calvin, et al.
(författare)
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Water-Induced Structural Rearrangements on the Nanoscale in Ultrathin Nanocellulose Films
- 2019
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 52:12, s. 4721-4728
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Tidskriftsartikel (refereegranskat)abstract
- Many nanoscale biopolymer building blocks with defect-free molecular structure and exceptional mechanical properties have the potential to surpass the performance of existing fossil-based materials with respect to barrier properties, load-bearing substrates for advanced functionalities, as well as light-weight construction. Comprehension and control of performance variations of macroscopic biopolymer materials caused by humidity-driven structural changes at the nanoscale are imperative and challenging. A long-lasting challenge is the interaction with water molecules causing reversible changes in the intrinsic molecular structures that adversely affects the macroscale performance. Using in situ advanced X-ray and neutron scattering techniques, we reveal the structural rearrangements at the nanoscale in ultrathin nanocellulose films with humidity variations. These reversible rearrangements are then correlated with wettability that can be tuned. The results and methodology have general implications not only on the performance of cellulose-based materials but also for hierarchical materials fabricated with other organic and inorganic moisture-sensitive building blocks.
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| 4. |
- Mangiapia, Gaetano, et al.
(författare)
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Cubosomes for ruthenium complex delivery: formulation and characterization
- 2011
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-6848 .- 1744-683X. ; 7:22, s. 10577-10580
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Tidskriftsartikel (refereegranskat)abstract
- An amphiphilic ruthenium-based molecule (DOPURu) with potential antineoplastic activity has been synthesized, and its aggregation behavior in the presence of phospholipids has been investigated. A very rich variety of aggregates has been found, spanning from vesicles to cubic bicontinuous phases. Cubosomes here presented represent one of the first systems with potential use for medical therapy.
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| 5. |
- Midtgaard, Søren Roi, et al.
(författare)
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Invisible detergents for structure determination of membrane proteins by small-angle neutron scattering
- 2018
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 285:2, s. 357-371
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Tidskriftsartikel (refereegranskat)abstract
- A novel and generally applicable method for determining structures of membrane proteins in solution via small-angle neutron scattering (SANS) is presented. Common detergents for solubilizing membrane proteins were synthesized in isotope-substituted versions for utilizing the intrinsic neutron scattering length difference between hydrogen and deuterium. Individual hydrogen/deuterium levels of the detergent head and tail groups were achieved such that the formed micelles became effectively invisible in heavy water (D2 O) when investigated by neutrons. This way, only the signal from the membrane protein remained in the SANS data. We demonstrate that the method is not only generally applicable on five very different membrane proteins but also reveals subtle structural details about the sarco/endoplasmatic reticulum Ca2+ ATPase (SERCA). In all, the synthesis of isotope-substituted detergents makes solution structure determination of membrane proteins by SANS and subsequent data analysis available to non-specialists. This article is protected by copyright. All rights reserved.
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| 6. |
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| 7. |
- Nylander, Tommy, et al.
(författare)
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Relationship between Structure and Fluctuations of Lipid Nonlamellar Phases Deposited at the Solid-Liquid Interface
- 2017
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 121:13, s. 2705-2711
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Tidskriftsartikel (refereegranskat)abstract
- The structure and dynamics of nanostructure films formed by mixtures of soy phosphatidylcholine and glycerol dioleate at the silicon aqueous interface were studied by grazing incidence neutron spin echo spectroscopy (GINSES), specular and off-specular neutron, reflectometry, and small-angle X-ray diffraction. Reverse hexagonal (Hr) and micellar cubic phase (Fd3m) layers at: the solid liquid interface have been identified with neutron reflectometry measurements. A preferred orientation of the liquid crystalline (LC) domains was observed only for the anisotropic,H-II phase. The size of the LC domains was found to be about 1 micrometer as estimated from the width of the diffraction peaks. GINSES revealed that the cubic phase forms rather rigid films. In comparison, the HE film was more flexible, appearing as a modified undulation spectrum of the cylinders due to the interaction with the substrate.
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| 8. |
- Wolff, Max, et al.
(författare)
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Grazing incidence neutron scattering for the study of solid–liquid interfaces
- 2023
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Ingår i: Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. - : Elsevier.
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Bokkapitel (refereegranskat)abstract
- Neutrons are characterized by a low absorption in many engineering materials. At the same time the scattering cross section of light elements, such as hydrogen and deuterium, may be large. These properties make neutron scattering experiments performed under grazing incidence geometry an excellent tool for the study of solid–liquid interfaces. In this review we describe the basic concepts of neutron reflection and grazing incidence scattering experiments as well as experimental procedures and sample cells. The full power of the method is exemplified on a range of science areas, including polymers, bio- and ionic liquid lubricants, electrolytes as well as bio-membranes or magnetic liquids.
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| 9. |
- Wolff, Max, et al.
(författare)
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Grazing incidence neutron scattering for the study of solid–liquid interfaces
- 2023
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Ingår i: Encyclopedia of Solid-Liquid Interfaces. - : Elsevier. ; , s. 1-1
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Neutrons are characterized by a low absorption in many engineering materials. At the same time the scattering cross section of light elements, such as hydrogen and deuterium, may be large. These properties make neutron scattering experiments performed under grazing incidence geometry an excellent tool for the study of solid–liquid interfaces. In this review we describe the basic concepts of neutron reflection and grazing incidence scattering experiments as well as experimental procedures and sample cells. The full power of the method is exemplified on a range of science areas, including polymers, bio- and ionic liquid lubricants, electrolytes as well as bio-membranes or magnetic liquids.
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