New Prospects for Particle Characterization Using Analytical Centrifugation with Sector‐Shaped Centerpieces

Uttinger, Maximilian J.; Boldt, Sebastián; Wawra, Simon E.; Freiwald, Tobias D.; Damm, Cornelia; Walter, Johannes; Lerche, D.

doi:10.1002/ppsc.202000108

Cited by 16 publications

(15 citation statements)

References 59 publications

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“…Moreover, the recent development of sector-shaped centerpieces for AC experiments enabled the measurement of a full diffusion-corrected sedimentation coefficient distribution. With this, it is possible to determine the hydrodynamic diameter distribution and the core-diameter distribution of gold nanoparticles alongside the stabilizer shell thickness of 3 nm only (Uttinger et al, 2020). (Huynh et al, 2016).…”

Section: D Analysis By Analytical Ultracentrifugationmentioning

confidence: 99%

Progress in Multidimensional Particle Characterization

Frank

Uttinger

Wawra

et al. 2022

KONA

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The properties of particle ensembles are defined by a complex multidimensional parameter space, namely particle size, shape, surface, structure, composition and their distributions. Macroscopic product properties are a direct result of these disperse particle properties. Therefore, the comprehensive multidimensional characterization of particle ensembles is a key task in any product design. However, the determination of complex property distributions is major challenge. We provide a broad overview of the current tools for multidimensional particle characterization. First, the mathematical handling of multidimensional (nD) property distribution is outlined as a necessary framework for the correct handling of nD particle size distributions (PSDs). Then, well-established techniques as well as recent developments with the potential to extract nD property distributions are reviewed. Exsitu imaging techniques like electron tomography or Raman spectroscopy with AFM co-localization, for instance, provide a resolution on the level of single particles but are limited in terms of sample statistics. A particular focus lies therefore on methods in the gas and the liquid phase, which provide multidimensional particle properties either directly or by a combination of one-dimensional techniques.

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Section: D Analysis By Analytical Ultracentrifugationmentioning

confidence: 99%

Progress in Multidimensional Particle Characterization

Frank

Uttinger

Wawra

et al. 2022

KONA

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“…It is reported that such convective instabilities arise primarily due to (i) temperature gradients across the cuvette, and (ii) rectangular shaped sample cell. Uttinger et al [61] reports presence of temperature gradients of 0.1-50 mK across the sample cell, at higher instrument operation temperatures, which might lead to convective rolls for nanoparticle suspensions over long experimental times. In order to reduce the effect of lateral temperature gradients, all measurements were performed at low temperature (~10 °C).…”

Section: Dispersion Characteristics 421 Sedimentation Fingerprintsmentioning

confidence: 99%

On the State and Stability of Fuel Cell Catalyst Inks

Bapat

Giehl²,

Kohsakowski³

et al. 2021

Preprint

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Catalyst layers (CL) as an active component of the catalyst coated membrane (CCM) form the heart of proton electrolyte membrane fuel cells (PEMFC). For optimum performance of the fuel cell, obtaining suitable structural and functional characteristics for the CL is crucial. Direct tuning of the microstructure and morphology of the CL is non-trivial; hence catalyst inks as catalyst layer precursors need to be modulated, which are then applied onto a membrane, to form the CCM. Obtaining favorable dispersion characteristics forms an important prerequisite in engineering catalyst inks for large scale manufacturing. In order to facilitate a knowledge-based approach for developing fuel cell inks, this work introduces new tools and methods to study both the dispersion state and stability characteristics, simultaneously. Catalyst inks were prepared using different processing methods which include stirring and ultrasonication. The proposed tools are used to characterize and elucidate the effects of the processing method. Structural characterization of the dispersed particles and their assemblages was carried out by means of transmission electron microscopy. Analytical centrifugation (AC) was used to study the state and stability of inks. Herein, we introduce new concepts, S score and stability trajectory, for a time-resolved assessment of inks in their native state using AC. The findings were validated and rationalized using transmittograms as a direct visualization technique. The flowability of inks was investigated by rheological measurements. It was found that probe sonication only up to an optimum amplitude leads to a highly stable colloidal ink.

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“…It is reported that such convective instabilities arise primarily due to (i) temperature gradients across the cuvette and (ii) rectangular shaped sample cells. Uttinger et al [60] recently reported the presence of temperature gradients of 0.1-50 mK across the sample cell, at higher instrument operation temperatures, which might lead to convective rolls for nanoparticle suspensions over long experimental times. In order to reduce the effect of lateral temperature gradients, all measurements were performed at low temperatures (~10 °C).…”

Section: Rheological Characterizationmentioning

confidence: 99%

On the State and Stability of Fuel Cell Catalyst Inks

Bapat

Giehl²,

Kohsakowski³

et al. 2021

Preprint

View full text Add to dashboard Cite

Catalyst layers (CL), as an active component of the catalyst coated membrane (CCM), form the heart of the proton electrolyte membrane fuel cell (PEMFC). For optimum performance of the fuel cell, obtaining suitable structural and functional characteristics for the CL is crucial. Direct tuning of the microstructure and morphology of the CL is non-trivial; hence catalyst inks as CL precursors need to be modulated, which are then applied onto a membrane to form the CCM. Obtaining favorable dispersion characteristics forms an important prerequisite in engineering catalyst inks for large scale manufacturing. In order to facilitate a knowledge-based approach for developing fuel cell inks, this work introduces new tools and methods to study both the dispersion state and stability characteristics, simultaneously. Catalyst inks were prepared using different processing methods, which include stirring and ultrasonication. The proposed tools are used to characterize and elucidate the effects of the processing method. Structural characterization of the dispersed particles and their assemblages was carried out by means of transmission electron microscopy. Analytical centrifugation (AC) was used to study the state and stability of the inks. Herein, we introduce new concepts, S score, and stability trajectory, for a time-resolved assessment of inks in their native state using AC. The findings were validated and rationalized using transmittograms as a direct visualization technique. The flowability of inks was investigated by rheological measurements. It was found that probe sonication only up to an optimum amplitude leads to a highly stable colloidal ink.

show abstract

New Prospects for Particle Characterization Using Analytical Centrifugation with Sector‐Shaped Centerpieces

Cited by 16 publications

References 59 publications

Progress in Multidimensional Particle Characterization

Progress in Multidimensional Particle Characterization

On the State and Stability of Fuel Cell Catalyst Inks

On the State and Stability of Fuel Cell Catalyst Inks

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