Interactive, Web-Based Calculator of Neutron and X-ray Reflectivity

Maranville, Brian B.

doi:10.6028/jres.122.034

Cited by 14 publications

(14 citation statements)

References 9 publications

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“…36 All data were corrected for background, sample cell scattering, and transmission. Data analysis was performed using SASview, 37 NIST software for calculation of neutron and X-ray reflectivity, 38 and OriginPro software.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Multiscale Microstructure, Composition, and Stability of Surfactant/Polymer Foams

et al. 2020

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Inclusion of polymer additives is a known strategy to improve foam stability, but questions persist about the amount of polymer incorporated in the foam and the resulting structural changes that impact material performance. Here, we study these questions in sodium dodecyl sulfate (SDS)/hydroxypropyl methylcellulose (HPMC) foams using a combination of flow injection QTOF mass spectrometry and small-angle neutron scattering (SANS) measurements leveraging contrast matching. Mass spectrometry results demonstrate polymer incorporation and retention in the foam during drainage by measuring the HPMC-to-SDS ratio. The results confirm a ratio matching the parent solution and stability over the time of our measurements. The SANS measurements leverage precise contrast matching to reveal detailed descriptions of the micellar structure (size, shape, and aggregation number) along with the foam film thickness. The presence of HPMC leads to thicker films, correlating with increased foam stability over the first 15–20 min after foam production. Taken together, mass spectrometry and SANS present a structural and compositional picture of SDS/HPMC foams and an approach amenable to systematic study for foams, gathering mechanistic insights and providing formulation guidance for rational foam design.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Multiscale Microstructure, Composition, and Stability of Surfactant/Polymer Foams

et al. 2020

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“…Since reflectivity observations are sensitive to the in-plane averaged neutron SLD profile perpendicular to the sample surface, the elastic coherent SLD values were used to determine concentration profiles. Web-based programs, reductus 33 and calculator of neutron and X-ray reflectivity, 34 were utilized for data reduction and modeling of the NR data, respectively.…”

Section: ■ Conclusionmentioning

confidence: 99%

Unusually High Concentration of Alkyl Ammonium Hydroxide in the Cation–Hydroxide–Water Coadsorbed Layer on Pt

Dumont

Spears

Hjelm

et al. 2019

ACS Appl. Mater. Interfaces

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Interactions between a catalyst and electrolyte have paramount importance for the performance of electrochemical devices. Here, we present the cation–hydroxide–water coadsorption on the Pt surface by a rotating disk electrode and neutron reflectometry. The rotating disk electrode experiments show that the current density of Pt rapidly dropped at hydrogen oxidation potentials due to tetramethylammonium hydroxide (TMAOH)–water coadsorption. Subsequent neutron reflectometry in 0.1 M TMAOD/D2O reveals that the thickness of the coadsorbed layer increased to 18 Å after 10.5 h exposure at 0.1 V vs reverse hydrogen electrode (RHE). The scattering length density analysis revealed that the TMAOD to water ratio in the coadsorbed layer was 4.5, which was significantly higher than the reportedly highest TMAOH concentration in aqueous solution. Finally, we discuss the potential impact of the coadsorbed layer on the performance and durability of alkaline membrane fuel cells, which sheds light on the material design of high-performance alkaline electrochemical devices.

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“…Four samples were aligned with the beam position at one time on the automatic trailer and measured in the ranges of q (0–0.1 Å –1 ). The experimental reflectivity data were fitted to obtain the scattering length density (SLD) profiles on a basis of the calculation of reflectivity profiles using the NCNR software (Reductus). , The uncertainty in reflectivity is less than the symbol size.…”

Section: Experimental Sectionmentioning

confidence: 99%

“…The experimental reflectivity data were fitted to obtain the scattering length density (SLD) profiles on a basis of the calculation of reflectivity profiles using the NCNR software (Reductus). 29,30 The uncertainty in reflectivity is less than the symbol size.…”

Section: ■ Introductionmentioning

confidence: 99%

Non-Equilibrium Phase Behavior of Immiscible Polymer-Grafted Nanoparticle Blends

et al. 2019

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Preferential attraction of polymer chains to the substrate [i.e., poly(methyl methacrylate) (PMMA) on the hydroxyl-terminated Si substrate] typically results in the initial phase separation of spin-cast immiscible linear polymer blends [i.e., polystyrene (PS)/PMMA] with a characteristic interfacial microstructure depending on their molecular weight. A formation of the undesired microstructure in those blends is inevitable because of the thermodynamic force driving their phase separation combined with relatively rapid dynamics in solution. In contrast, the polymer ligands, which are grafted from nanoparticles, are capable of limited segmental interactions in the presence of segmental contacts of chemically distinct chains as well as hindered mobility by interpenetration (or entanglement) and thus exhibit a homogeneous but non-equilibrium phase behavior. Here, the microstructure of the blends consisting of immiscible polymer-grafted nanoparticles (PGNPs) was identified by their neutron reflectivity, in which the scattering length density was controlled by tethering deuterated PS on silica NPs. We demonstrate that the single-phase homogeneous microstructure is attributed to a significantly reduced particle dynamics arising from the cooperative motion (or interpenetration) of polymer ligands during vitrification of PGNP films despite a relatively high degree of segregation NχS/MMA. Furthermore, the slower segmental interactions of polymer ligands promote the thermal stability of the PGNP blends in the kinetically quenched non-equilibrium state. This suggests a crucial role of polymer ligands to determine the relevant properties relying on their microstructures in a wide range of blending approaches utilizing nanoparticles and polymers.

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Interactive, Web-Based Calculator of Neutron and X-ray Reflectivity

Cited by 14 publications

References 9 publications

Multiscale Microstructure, Composition, and Stability of Surfactant/Polymer Foams

Multiscale Microstructure, Composition, and Stability of Surfactant/Polymer Foams

Unusually High Concentration of Alkyl Ammonium Hydroxide in the Cation–Hydroxide–Water Coadsorbed Layer on Pt

Non-Equilibrium Phase Behavior of Immiscible Polymer-Grafted Nanoparticle Blends

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