Towards generalized data reduction on a chopper-based time-of-flight neutron reflectometer

Gutfreund, Philipp; Saerbeck, Thomas; Ma, González; Pellegrini, E.; Laver, Mark; Dewhurst, C. D.; Cubitt, R.

doi:10.1107/s160057671800448x

Cited by 56 publications

(57 citation statements)

References 25 publications

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“…The samples were under-illuminated for both the D17 and Figaro measurements and overilluminated at Inter. To calculate the specular reflectivity curves from the raw data obtained from the incident and reflected neutron beams at the ILL, we used the COSMOS data reduction program 72 . A data-reduction code written in Python at ISIS was used to produce reflectivity curves from the raw data from Inter.…”

Section: Methodsmentioning

confidence: 99%

Interfacial width and phase equilibrium in polymer-fullerene thin-films

et al. 2019

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Domain composition and interfacial structure are critical factors in organic photovoltaic performance. Here, we report neutron reflectivity, grazing-incidence X-ray diffraction and atomic force microscopy measurements of polymer/fullerene thin-films to test a hypothesis that these partially miscible blends rapidly develop composition profiles consisting of coexisting phases in liquid-liquid equilibrium. We study a range of polymer molecular weights between 2 and 300 kg mol −1 , annealing temperatures between 120 and 170 o C, and timescales up to 10 min, yielding over 50 distinct measurement conditions. Model bilayers of fullerene-derivatives and polystyrene enable a rigorous examination of theoretical predictions of the effect of polymer mass and interaction parameter on the compositions, ϕ, and interfacial width, w, of the coexistent phases. We independently measure ϕ and w and find that both Flory-Huggins mean-field-theory and key aspects of self-consistent-field-theory are remarkably consistent with experiment. Our findings pave the way for predictive composition and interface design in organic photovoltaics based on simple experimental measurements and equilibrium thermodynamic theory.

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Section: Methodsmentioning

confidence: 99%

Interfacial width and phase equilibrium in polymer-fullerene thin-films

et al. 2019

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“…The raw data was converted to absolute reflectivities as a function of momentum transfer by using the data reduction software COSMOS. 40 N-REX+ 41 at FRM2 is an angle dispersive fixed wavelength (4.4 Å, resolution 3%) reflectometer with horizontal sample geometry. A 20 Â 20 cm 2 position sensitive detector was used allowing for specular and off-specular reflectivity measurements although only the specular data was analyzed here.…”

Section: Neutron Reflectometrymentioning

confidence: 99%

Swelling, dewetting and breakup in thin polymer films for cultural heritage

et al. 2020

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“…The data were reduced using COSMOS. 47 Data of the samples were normalized to a measurement of pure D2O with fits to the total reflection for the data recorded at θ = 0.62° and a reflectivity model for the data recorded at θ = 3.8°. The latter approach was adopted in order to minimize the introduction of systematic errors in the data recorded at the higher incident angle, which occurs on a level of ~3% in the usual procedure of stitching them to the data from the lower incident angle to achieve good overlap.…”

Section: Nr Data Acquisitionmentioning

confidence: 99%

Structure of surfactant and phospholipid monolayers at the air/water interface modeled from neutron reflectivity data

Campbell

Saaka

Shao

et al. 2018

Journal of Colloid and Interface Science

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Specular neutron reflectometry is a powerful technique to resolve interfacial compositions and structures in soft matter. Surprisingly however, even after several decades, a universal modeling approach for the treatment of data of surfactant and phospholipid monolayers at the air/water interface has not yet been established. To address this shortcoming, first a systematic evaluation of the suitability of different models is presented. The result is a comprehensive validation of an optimum model, which is evidently much needed in the field, and which we recommend as a starting point for future data treatment. While its limitations are openly discussed, consequences of failing to take into account various key aspects are critically examined and the systematic errors quantified. On the basis of this physical framework, we go on to show for the first time that neutron reflectometry can be used to quantify directly in situ at the air/water interface the extent of acyl chain compaction of phospholipid monolayers with respect to their phase. The achieved precision of this novel quantification is ∼10%. These advances together enhance significantly the potential for exploitation in future studies data from a broad range of systems including those involving synthetic polymers, proteins, DNA, nanoparticles and drugs.

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Towards generalized data reduction on a chopper-based time-of-flight neutron reflectometer

Cited by 56 publications

References 25 publications

Interfacial width and phase equilibrium in polymer-fullerene thin-films

Interfacial width and phase equilibrium in polymer-fullerene thin-films

Swelling, dewetting and breakup in thin polymer films for cultural heritage

Structure of surfactant and phospholipid monolayers at the air/water interface modeled from neutron reflectivity data

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