The novel reflectometer REFSANS for analyses of liquid and soft surfaces at the new research reactor FRM-II in Munich, Germany

Kampmann, R.; Haese, Martin; Marmotti, M.; Burmester, J.; Deriglazov, V. V.; Syromiatnikov, V.; Okorokov, A. I.; Frisius, F.; Tristl, M.; Sackmann, E.

doi:10.1007/s003390201755

Cited by 10 publications

(6 citation statements)

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“…The measurements were performed at the REFSANS neutron reflectometer at FRM II in Munich. REFSANS is a time-of-flight (ToF) instrument for reflectometry at the solid–liquid interface. , We make use of isotope labeling (i.e., deuteration of the lipid chains) and contrast variation by exchanging D 2 O against a mixture of H 2 O/D 2 O. This allows us to determine the volume fraction of the lipids ( x 1 ) and the hydration water fraction ( x 2 ) as a function of depth as well as the scattering length density (SLD) profile of the bilayer.…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Distribution of Anionic Phospholipids in Supported Lipid Bilayers

Stanglmaier¹,

Hertrich²,

Fritz³

et al. 2012

Langmuir

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Lipid bilayers with a controlled content of anionic lipids are a prerequisite for the quantitative study of hydrophobic-electrostatic interactions of proteins with lipid bilayers. Here, the asymmetric distribution of zwitterionic and anionic lipids in supported lipid bilayers is studied by neutron reflectometry. We prepare POPC/POPS (3:1) unilamellar vesicles in a high-salt-concentration buffer. Initially, no fusion of the vesicles to a SiO(2) surface is observed over hours and days. Once the isotonic buffer is exchanged with hypotonic buffer, vesicle fusion and bilayer formation occur by osmotic shock. Neutron reflectivity on the bilayers formed this way reveals the presence of anionic lipids (d(31)-POPS) in the outer bilayer leaflet only, and no POPS is observed in the leaflet facing the SiO(2) substrate. We argue that this asymmetric distribution of POPS is induced by the electrostatic repulsion of the phosphatidylserines from the negatively charged hydroxy surface groups of the silicon block. Such bilayers with controlled and high contents of anionic lipids in the outer leaflet are versatile platforms for studying anionic lipid protein interactions that are key elements in signal transduction pathways in the cytoplasmic leaflet of eukaryotic cells.

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Section: Methodsmentioning

confidence: 99%

Asymmetric Distribution of Anionic Phospholipids in Supported Lipid Bilayers

Stanglmaier¹,

Hertrich²,

Fritz³

et al. 2012

Langmuir

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“…The wavelength resolution of the incident beam is controlled using a double high-speed chopper system. The separation distance between the choppers was about 2.31 m and the system was operated as described by Kampmann et al (2002Kampmann et al ( , 2003Kampmann et al ( , 2004Kampmann et al ( , 2006. The slits on both choppers can be varied between 0 and 120 .…”

Section: Time-of-flight Gisansmentioning

confidence: 99%

Structural investigation of thin diblock copolymer films using time-of-flight grazing-incidence small-angle neutron scattering

Metwalli

Moulin²,

Rauscher

et al. 2010

J Appl Cryst

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The depth‐dependent morphology of the microphase separation structure in thin block copolymer films is examined using non‐destructive time‐of‐flight grazing‐incidence small‐angle neutron scattering. The structure of a cylinder‐forming diblock copolymer, polystyrene(deuterated)‐block‐polyisoprene, in contact with either a low‐ or a high‐energy substrate surface is investigated. A systematic identification of the components of the polymer film at different depths is achieved by utilizing the material characteristic Yoneda peak. For the polymer film attached to the low‐surface‐energy aminosilane‐coated substrate, a morphology transition from lamellar at the substrate–polymer interface, via perforated lamellar in the film bulk, to an ill‐defined structure at the polymer–air interface is observed. This phase transition along the film normal is due to the competition between the surface‐induced morphological changes and the stable cylindrical bulk morphology of the diblock copolymer. In contrast, on the high‐energy surface no pronounced ordering is found for the applied conditions.

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“…GISANS experiments were performed in TOF mode at the horizontal reflectometer REFSANS (Kampmann et al, 2002(Kampmann et al, , 2003 at the Munich research reactor Heinz Maier-Leibnitz (MLZ). The TOF-GISANS measurements used an incident angle of 0.50 , a sample-detector distance of 10.7 m and a neutron wavelength band of 0.25-1.49 nm selected by a chopper using a resolution Á/ = 10%.…”

Section: Grazing-incidence Small-angle Neutron Scatteringmentioning

confidence: 99%

Morphology determination of defect-rich diblock copolymer films with time-of-flight grazing-incidence small-angle neutron scattering

et al. 2014

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The complex nanomorphology of a defect‐rich deuterated poly(styrene‐block‐methyl methacrylate), P(S‐b‐MMAd), diblock copolymer film is determined with a combination of grazing‐incidence small‐angle neutron scattering (GISANS) and time‐of‐flight (TOF) mode. TOF‐GISANS enables the simultaneous performance of several GISANS measurements that differ in wavelength. The resulting set of GISANS data covers different ranges of the scattering vector and has different scattering depths. Thus surface‐sensitive and bulk‐sensitive measurements can be performed simultaneously. The P(S‐b‐MMAd) film exhibits a lamellar microphase separation structure, which because of the defects is arranged into small, randomly oriented grains, composed of four–five lamellar repetitions. In the near‐surface region, the lamellar structure is oriented parallel to the substrate, which explains the smooth surface found with atomic force microscopy.

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The novel reflectometer REFSANS for analyses of liquid and soft surfaces at the new research reactor FRM-II in Munich, Germany

Cited by 10 publications

References 0 publications

Asymmetric Distribution of Anionic Phospholipids in Supported Lipid Bilayers

Asymmetric Distribution of Anionic Phospholipids in Supported Lipid Bilayers

Structural investigation of thin diblock copolymer films using time-of-flight grazing-incidence small-angle neutron scattering

Morphology determination of defect-rich diblock copolymer films with time-of-flight grazing-incidence small-angle neutron scattering

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