Mass-fractal growth in niobia/silsesquioxane mixtures: a small-angle X-ray scattering study

Besselink, Rogier; Elshof, Johan E. ten

doi:10.1107/s1600576714017105

Cited by 3 publications

(5 citation statements)

References 51 publications

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“…The SAXS results shown in Figure 2A, measured on the asprepared samples, reveal that the samples all contain molecular aggregates forming spherical objects consisting of Gaussian chains, as evidenced by the high q power-law slope of −2 (see fractal power-law exponent D f ∼ 2 in Table 1). 35 In other words, the primary particles are in a well-solvated state (i.e., polymerrich water-containing domains). The shape of the primary particles is believed to be spherical since no power-law scattering was found in the very small q region; therefore, we denote the primary particle as a globule.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Low-Temperature Ionic Conductivity Enhanced by Disrupted Ice Formation in Polyampholyte Hydrogels

Charaya

Bernard

et al. 2018

Macromolecules

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The phase behavior of water in hydrogels has a broad impact on many health and energy applications. Our previous study showed that polyampholyte hydrogel has the potential to be used as an aqueous gel electrolyte in electrochemical storage devices at −30 °C due to enhanced low-temperature conductivity. In this study, we detail the impact polymer structure has on this enhanced conductivity, explaining this finding with a model charge-balanced polyampholyte, poly(4-vinylbenzenesulfonate-co-[3-(methacryloylamino)propyl]trimethylammonium chloride), a hydrogel whose polymer and water structures are probed by variable-temperature SAXS, WAXS, and solid-state NMR spectroscopy. SAXS results at room temperature indicate a networked globule structure in the charge-balanced polyampholyte hydrogels. The globular radius of gyration is ∼2.5 nm, whereas the globular size and its clustering structure are dependent on synthesis parameters. Variable-temperature SAXS data reveal a temperature-dependent structure evolution of the polyampholyte hydrogel. An interconnected globular network structure of polymer-rich phase at low temperature, observed by electron microscopy, is suggested to preserve ion-conducting channels of nonfrozen water molecules at low temperatures. This hypothesis is further supported by solid-state NMR spectroscopy. Together these findings provide macromolecular-and molecular-level insight that may be used to design gel electrolytes for enhanced low-temperature performance.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Low-Temperature Ionic Conductivity Enhanced by Disrupted Ice Formation in Polyampholyte Hydrogels

Charaya

Bernard

et al. 2018

Macromolecules

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“…Other fractal systems exist, including surface and pore fractals . From the slope of the scattering curve, it is possible to understand the mechanism of aggregation, such as reaction limited or diffusion limited growth. − …”

Section: Particle Scatteringmentioning

confidence: 99%

“…More recently, Besselink and ten Elshof used a step function, or Heaviside function H , as where the exponential function and H represent the particle size and internal structures, respectively. In addition, they used the Schultz–Zimm distribution function for the distribution of ξ.…”

Section: Correlation Function Approachmentioning

confidence: 99%

Small Angle X-ray Scattering for Nanoparticle Research

2016

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X-ray scattering is a structural characterization tool that has impacted diverse fields of study. It is unique in its ability to examine materials in real time and under realistic sample environments, enabling researchers to understand morphology at nanometer and angstrom length scales using complementary small and wide angle X-ray scattering (SAXS, WAXS), respectively. Herein, we focus on the use of SAXS to examine nanoscale particulate systems. We provide a theoretical foundation for X-ray scattering, considering both form factor and structure factor, as well as the use of correlation functions, which may be used to determine a particle's size, size distribution, shape, and organization into hierarchical structures. The theory is expanded upon with contemporary use cases. Both transmission and reflection (grazing incidence) geometries are addressed, as well as the combination of SAXS with other X-ray and non-X-ray characterization tools. We conclude with an examination of several key areas of research where X-ray scattering has played a pivotal role, including in situ nanoparticle synthesis, nanoparticle assembly, and operando studies of catalysts and energy storage materials. Throughout this review we highlight the unique capabilities of X-ray scattering for structural characterization of materials in their native environment.

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“…Mixing Nb(OEt) 5 (NPE) into a prehydrolyzed acidic BTESE sol in ethanol at 298-333 K was shown to lead to NbO x clusters within the first 10 s of reaction [34,35]. The presence or absence of preydrolyzed BTESE has a negligible influence on the size of these clusters.…”

Section: Incorporation Of Transition Metal Cationsmentioning

confidence: 99%

“…The presence or absence of preydrolyzed BTESE has a negligible influence on the size of these clusters. However, their subsequent growth and agglomeration is suppressed by the presence of BTESE [35], because the niobia particles/clusters become encapsulated by BTESE-derived moieties.…”

Section: Incorporation Of Transition Metal Cationsmentioning

confidence: 99%

Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

Elshof

Dral

2015

J Sol-Gel Sci Technol

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Supported microporous organosilica membranes made from bridged silsesquioxane precursors by an acid-catalyzed sol-gel process have demonstrated a remarkable hydrothermal stability in pervaporation and gas separation processes, making them the first generation of ceramic molecular sieving membranes with sufficient performance under industrially relevant conditions. The commercial availability of various a,x-bis(trialkoxysilyl)alkane and 1,4-bis(trialkoxysilyl)benzene precursors facilitates the tailoring of membrane properties like pore size and surface chemistry via the choice of precursor(s) and process variables. Here, we describe the engineering of sols for making supported microporous thin films, discuss the thermal and hydrothermal stability of microporous organosilicas and give a short overview of the developments and applications of these membranes in liquid and gas separation processes since their first report in 2008.Graphical Abstract

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Mass-fractal growth in niobia/silsesquioxane mixtures: a small-angle X-ray scattering study

Abstract: The nucleation and growth of niobium pentaethoxide-derived clusters in ethanol was monitored at 298–333 K by small-angle X-ray scattering. The data were analyzed with a newly derived model for polydisperse mass-fractal-like structures.

Cited by 3 publications

References 51 publications

Low-Temperature Ionic Conductivity Enhanced by Disrupted Ice Formation in Polyampholyte Hydrogels

Low-Temperature Ionic Conductivity Enhanced by Disrupted Ice Formation in Polyampholyte Hydrogels

Small Angle X-ray Scattering for Nanoparticle Research

Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

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