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Alginate is an important part of the extracellular polymeric substances excreted by microorganisms giving rise to biofouling on reverse osmosis membranes in desalination plants for water treatment. We present a small-angle neutron scattering study on aggregation of alginate when exposed to an aqueous salt solution simulating the reverse osmosis concentrate of a wastewater reclamation plant. We explored the behavior of alginate as dissolved molecule and as grafted to the surface of gold nanoparticles thereby simulating the condition of alginate attached at the surface of a membrane. The behavior of dissolved and grafted alginate was different when exposed to the simulation solution. The dissolved alginate aggregates to a gel like structure whereas the grafted alginate induces formation of 0.2 μm large particles. These particles form stable composites within few seconds with volume fraction of about half mineral and half gold nano-particles. [ABSTRACT FROM AUTHOR]

In soft matter small angle neutron scattering (SANS) studies at large Q values, incoherent scattering becomes the dominant signal. In the Q-range of interest to this work, from 0.2 Å−1 to about 1.0 Å−1, the coherent scattering from the typical protein or polymer in a D2O buffer solution inevitably drops one to two orders of magnitude or more below the total scattering. Even after careful and accurate subtraction of the measured D2O buffer scattering, the remaining corrected, i.e. sample-only, signal will still be dominated by diffuse incoherent scattering from hydrogen in the sample itself. This is the exact region of interest when one wishes to probe the structural changes in “living” proteins caused by interactions and motions related to function. To further complicate the problem, there is strong motivation to measure this Q-regime at very low concentrations because it has been shown with wide angle X-ray scattering that proteins can undergo concentration-dependent structural changes that rapidly increase below concentrations of about 5% [1] motivating the study of protein solutions at ever lower concentrations. In this case the signal from the protein will inevitably become much less than the scattering of the D2O buffer solution it is contained in. Polarization analysis offers the opportunity to separate the weak coherent signal from the larger incoherent signal and perhaps enable measurements under the conditions described above. This paper will address the issues associated with the correct separation of coherent and incoherent scattering for soft matter samples. We have performed tests measurements on KWS2 which show the viability of the method on a protonated α-lactalbumin solution at 2.5% (1mm thick) and 0.25% (2mm thick) concentrations in a D2O buffer solution. Additionally describe a the method of implementation using 3He spin filters, some practical considerations, and future plans for a dedicated device at the JCNS. [ABSTRACT FROM AUTHOR]

Highlights • Reproducible growth method of FePd with high PMA and parallely aligned magnetic domains. • Pseudo-reversible manipulation of the domain pattern after applying a saturating magnetic field. • Simulation of the Q y - Q z -map of a GISANS measurement using the Distorted Wave Born Approximation. Abstract L1 0 -ordered FePd thin films with strong perpendicular magnetic anisotropy and self-organized domain patterns have been prepared using molecular beam epitaxy. We demonstrate reproducible growth methods for controlling the strength of the anisotropy and the lateral domain patterns. Neutron scattering experiments have been used to probe the FePd domain structure and were compared with simulations in the framework of the Distorted Wave Born Approximation. [ABSTRACT FROM AUTHOR]

Small angle X-ray and neutron scattering on Cd and S doped glass annealed at 600 °C shows after the first 12 h nucleation and growth of spherical CdS nanoparticles with a radius of up to 34±4 Å. After the nucleation is completed after 24 h, further growth in this amorphous environment is governed by oriented particle attachment mechanism as found for a liquid medium. Towards 48 h the particle shape has changed into spheroidal with short and long axis of 40±2 Å and 120±2 Å, respectively. [ABSTRACT FROM AUTHOR]