Exhibitive Nano-to-Micron Scale Sedimentation Dynamics of Colloidal Formulations Through Direct Visualization

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Doris Segets
Keyword(s):  
Fuel Cell ◽  
Colloidal Stability ◽  
Silica Nanoparticle ◽  
Data Interpretation ◽  
Colloidal Systems ◽  
Time Resolved ◽  
Knowledge Based ◽  
Sedimentation Behavior ◽  
Nanoparticle Dispersions ◽  
Analytical Centrifugation

The study of sedimentation behavior of nanoparticle dispersions is important for revealing particle size and colloidal stability characteristics. Quantitative appraisal of real-world colloidal systems in their native state, is key for replacing prevailing empiricism in formulation science by knowledge-based design. Herein, we choose fuel cell inks as one case-example amongst many other possibilities to present a new visualization technique, called <i>Transmittogram</i>. This technique readily depicts the time-resolved settling behavior of solid-liquid dispersions, measured by analytical centrifugation (AC). Although AC enables the causal examination of agglomeration, settling, and creaming behavior of dispersions, along with its consequent effect on structure formation and product properties, the understanding of the main transmission readout is often non-intuitive and complex. Transmittograms are, therefore, the missing link for straightforward data interpretation. First, we illustrate the utility of transmittogram analysis using model silica nanoparticle systems and further validate it against known characteristics of the system. Then, we demonstrate the application of transmittograms to characterize fuel cell inks, showing the strength of the approach in deconvoluting and distilling information to the reader. Finally, we discuss the potential of the technique for routine analysis using analytical centrifugation.<br>

Exhibitive Nano-to-Micron Scale Sedimentation Dynamics of Colloidal Formulations Through Direct Visualization

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Doris Segets
Keyword(s):  
Fuel Cell ◽  
Colloidal Stability ◽  
Silica Nanoparticle ◽  
Data Interpretation ◽  
Colloidal Systems ◽  
Time Resolved ◽  
Knowledge Based ◽  
Sedimentation Behavior ◽  
Nanoparticle Dispersions ◽  
Analytical Centrifugation

The study of sedimentation behavior of nanoparticle dispersions is important for revealing particle size and colloidal stability characteristics. Quantitative appraisal of real-world colloidal systems in their native state, is key for replacing prevailing empiricism in formulation science by knowledge-based design. Herein, we choose fuel cell inks as one case-example amongst many other possibilities to present a new visualization technique, called <i>Transmittogram</i>. This technique readily depicts the time-resolved settling behavior of solid-liquid dispersions, measured by analytical centrifugation (AC). Although AC enables the causal examination of agglomeration, settling, and creaming behavior of dispersions, along with its consequent effect on structure formation and product properties, the understanding of the main transmission readout is often non-intuitive and complex. Transmittograms are, therefore, the missing link for straightforward data interpretation. First, we illustrate the utility of transmittogram analysis using model silica nanoparticle systems and further validate it against known characteristics of the system. Then, we demonstrate the application of transmittograms to characterize fuel cell inks, showing the strength of the approach in deconvoluting and distilling information to the reader. Finally, we discuss the potential of the technique for routine analysis using analytical centrifugation.<br>

scholarly journals Exhibitive Nano-to-Micron Scale Sedimentation Dynamics of Colloidal Formulations Through Direct Visualization

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Doris Segets
Keyword(s):  
Fuel Cell ◽  
Colloidal Stability ◽  
Silica Nanoparticle ◽  
Data Interpretation ◽  
Colloidal Systems ◽  
Time Resolved ◽  
Knowledge Based ◽  
Sedimentation Behavior ◽  
Nanoparticle Dispersions ◽  
Analytical Centrifugation

The study of sedimentation behavior of nanoparticle dispersions is important for revealing particle size and colloidal stability characteristics. Quantitative appraisal of real-world colloidal systems in their native state, is key for replacing prevailing empiricism in formulation science by knowledge-based design. Herein, we choose fuel cell inks as one case-example amongst many other possibilities to present a new visualization technique, called <i>Transmittogram</i>. This technique readily depicts the time-resolved settling behavior of solid-liquid dispersions, measured by analytical centrifugation (AC). Although AC enables the causal examination of agglomeration, settling, and creaming behavior of dispersions, along with its consequent effect on structure formation and product properties, the understanding of the main transmission readout is often non-intuitive and complex. Transmittograms are, therefore, the missing link for straightforward data interpretation. First, we illustrate the utility of transmittogram analysis using model silica nanoparticle systems and further validate it against known characteristics of the system. Then, we demonstrate the application of transmittograms to characterize fuel cell inks, showing the strength of the approach in deconvoluting and distilling information to the reader. Finally, we discuss the potential of the technique for routine analysis using analytical centrifugation.<br>

scholarly journals On the State and Stability of Fuel Cell Catalyst Inks

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Christopher Giehl ◽  
Sebastian Kohsakowski ◽  
Volker Peinecke ◽  
Michael Schäffler ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Large Scale ◽  
Catalyst Layer ◽  
The State ◽  
Time Resolved ◽  
Electrolyte Membrane ◽  
Knowledge Based ◽  
Catalyst Layers ◽  
Dispersion State ◽  
Means Of Transmission

<p>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, <i>S score</i> and <i>stability trajectory</i>, 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.</p>

scholarly journals On the State and Stability of Fuel Cell Catalyst Inks

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Christopher Giehl ◽  
Sebastian Kohsakowski ◽  
Volker Peinecke ◽  
Michael Schäffler ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Large Scale ◽  
Catalyst Layer ◽  
The State ◽  
Time Resolved ◽  
Electrolyte Membrane ◽  
Knowledge Based ◽  
Catalyst Layers ◽  
Dispersion State ◽  
Means Of Transmission

<p>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, <i>S score</i> and <i>stability trajectory</i>, 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.</p>

scholarly journals On the State and Stability of Fuel Cell Catalyst Inks

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Christopher Giehl ◽  
Sebastian Kohsakowski ◽  
Volker Peinecke ◽  
Michael Schäffler ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Large Scale ◽  
Catalyst Layer ◽  
The State ◽  
Time Resolved ◽  
Electrolyte Membrane ◽  
Knowledge Based ◽  
Catalyst Layers ◽  
Dispersion State ◽  
Means Of Transmission

<p>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, <i>S score</i> and <i>stability trajectory</i>, 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.</p>

scholarly journals On the State and Stability of Fuel Cell Catalyst Inks

2021 ◽  
Author(s):  
Shalmali Bapat ◽  
Christopher Giehl ◽  
Sebastian Kohsakowski ◽  
Volker Peinecke ◽  
Michael Schäffler ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Large Scale ◽  
The State ◽  
Time Resolved ◽  
Electrolyte Membrane ◽  
Knowledge Based ◽  
Catalyst Layers ◽  
Transmission Electron ◽  
Dispersion State ◽  
Means Of Transmission

<p></p><p>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.<br></p><br><p></p>

scholarly journals On the State and Stability of Fuel Cell Catalyst Inks

2021 ◽  
Author(s):  
Shalmali Bapat ◽  
Christopher Giehl ◽  
Sebastian Kohsakowski ◽  
Volker Peinecke ◽  
Michael Schäffler ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Large Scale ◽  
The State ◽  
Time Resolved ◽  
Electrolyte Membrane ◽  
Knowledge Based ◽  
Catalyst Layers ◽  
Transmission Electron ◽  
Dispersion State ◽  
Means Of Transmission

<p></p><p>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.<br></p><br><p></p>

Silica nanoparticle dispersions in homopolymer versus block copolymer

2007 ◽  
Vol 45 (16) ◽  
pp. 2284-2299 ◽  
Author(s):  
Qiang Lan ◽  
Lorraine F. Francis ◽  
Frank S. Bates
Keyword(s):  
Block Copolymer ◽  
Silica Nanoparticle ◽  
Nanoparticle Dispersions ◽  
Versus Block

Phase-Change Heat Transfer Measurements Using Temperature-Sensitive Paints

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Husain Al Hashimi ◽  
Caleb F. Hammer ◽  
Michel T. Lebon ◽  
Dan Zhang ◽  
Jungho Kim
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Uv Light ◽  
Flow Boiling ◽  
Low Cost ◽  
Data Interpretation ◽  
Temperature Sensitive ◽  
Time Resolved ◽  
Light Emitting ◽  
Phase Change Heat Transfer

Techniques based on temperature-sensitive paints (TSP) to measure time-resolved temperature and heat transfer distributions at the interface between a wall and fluid during pool and flow boiling are described. The paints are excited using ultraviolet (UV) light emitting diodes (LEDs), and changes in fluorescence intensity are used to infer local temperature differences across a thin insulator from which heat flux distribution is obtained. Advantages over infrared (IR) thermometry include the ability to use substrates that are opaque to IR (e.g., glass, plexiglass and plastic films), use of low-cost optical cameras, no self-emission from substrates to complicate data interpretation, high speed, and high spatial resolution. TSP-based methods to measure wall heat transfer distributions are validated and then demonstrated for pool and flow boiling.

Sign in / Sign up

Export Citation Format

Share Document