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Material Science

Monitor Polymer Transitions with a combined RheoRaman System


Monitor Polymer Transitions with a combined RheoRaman System

Register for this webinar by logging in or signing up below.

The use of a coupled rheometer and Raman spectrometer for obtaining comprehensive insight into materials behavior is presented.  Rheology is the analytical method of choice to correlate the absolute flow and deformation characteristics of a material with its behavior towards processing or application steps. Rheology as an integral method, however, only yields answers on the bulk properties of the material. It does not provide any insights into what is happening at the molecular level when rheological changes are observed. 

Raman spectroscopy has shown its ability as a powerful, effective and non-invasive method for chemical analysis. In addition, Raman spectroscopy is sensitive to the structural composition of materials, providing the capability to differentiate between a material’s molten and crystalline forms.  Coupling a rheometer with a Raman spectrometer provides direct correlation of molecular composition and structure to the observed mechanical properties. This is extremely useful for studying phase transition behavior, e.g. the crystallization behavior of polymer melts during processing. It can also provide insight for in-situ characterization and monitoring which can be challenging when working with on-line techniques as only relative flow fields are characterized.

Finally, the coupling gives the researcher the advantage of maximizing and synchronizing the information gathered from a single measurement, as compared to sequential measurements, as well as enabling the observation of transient information on their materials during fast processing conditions.

In this webinar we will present results obtained with the new combination of a Thermo Scientific(TM) HAAKE(TM) MARS(TM) rheometer with a Thermo Scientific(TM) iXR Raman spectrometer.

  • See how Raman and Rheology can provide more information about your sample
     
  • Show advantage of a multi-modal analysis
     
  • See polymer phase transitions
     
  • Introduce the iXR Raman Spectrometer, the first Ramna spectrometer developed specifically for integration and multi-modal analysis analysis techniques.

Speakers:

David Drapcho, Thermo Fisher Scientific

Joe d'Angelo, (Moderator), Materials Science Publisher, Elsevier.

 

When you register for this webinar your registration details will be passed to the sponsor who will provide you with information relevant to this topic.

Republished by Plato

Published

on


Monitor Polymer Transitions with a combined RheoRaman System

Register for this webinar by logging in or signing up below.

The use of a coupled rheometer and Raman spectrometer for obtaining comprehensive insight into materials behavior is presented.  Rheology is the analytical method of choice to correlate the absolute flow and deformation characteristics of a material with its behavior towards processing or application steps. Rheology as an integral method, however, only yields answers on the bulk properties of the material. It does not provide any insights into what is happening at the molecular level when rheological changes are observed. 

Raman spectroscopy has shown its ability as a powerful, effective and non-invasive method for chemical analysis. In addition, Raman spectroscopy is sensitive to the structural composition of materials, providing the capability to differentiate between a material’s molten and crystalline forms.  Coupling a rheometer with a Raman spectrometer provides direct correlation of molecular composition and structure to the observed mechanical properties. This is extremely useful for studying phase transition behavior, e.g. the crystallization behavior of polymer melts during processing. It can also provide insight for in-situ characterization and monitoring which can be challenging when working with on-line techniques as only relative flow fields are characterized.

Finally, the coupling gives the researcher the advantage of maximizing and synchronizing the information gathered from a single measurement, as compared to sequential measurements, as well as enabling the observation of transient information on their materials during fast processing conditions.

In this webinar we will present results obtained with the new combination of a Thermo Scientific(TM) HAAKE(TM) MARS(TM) rheometer with a Thermo Scientific(TM) iXR Raman spectrometer.

  • See how Raman and Rheology can provide more information about your sample
     
  • Show advantage of a multi-modal analysis
     
  • See polymer phase transitions
     
  • Introduce the iXR Raman Spectrometer, the first Ramna spectrometer developed specifically for integration and multi-modal analysis analysis techniques.

Speakers:

David Drapcho, Thermo Fisher Scientific

Joe d’Angelo, (Moderator), Materials Science Publisher, Elsevier.

When you register for this webinar your registration details will be passed to the sponsor who will provide you with information relevant to this topic.

Source: https://www.materialstoday.com/amorphous/webinars/monitor-polymer-transitions-combined-rheoraman-sys/

Material Science

Weak force has strong impact on metal nanosheets


A transmission electron microscope image by Rice University scientists shows a silver nanosheet deformed by a particle, which forms flower-shaped stress contours in the nanosheet that indicate a bump. Image: The Jones Lab/Rice University.
A transmission electron microscope image by Rice University scientists shows a silver nanosheet deformed by a particle, which forms flower-shaped stress contours in the nanosheet that indicate a bump. Image: The Jones Lab/Rice University.

New research has revealed that the hills are alive with the force of van der Walls. Researchers at Rice University have found that nature's ubiquitous 'weak' force is sufficient to indent rigid nanosheets, extending their potential for use in nanoscale optics or catalytic systems.

Changing the shape of nanoscale particles changes their electromagnetic properties, said Matt Jones, an assistant professor of chemistry and an assistant professor of materials science and nanoengineering at Rice University. That makes the phenomenon worth further study.

"People care about particle shape, because the shape changes its optical properties," Jones said. "This is a totally novel way of changing the shape of a particle." He and his colleagues report their work in a paper in Nano Letters.

Van der Waals is a weak force that allows neutral molecules to attract one another through randomly fluctuating dipoles, or separated opposite charges, depending on distance. Though small, its effects can be seen in the macro world, like when geckos walk up walls.

"Van der Waals forces are everywhere and, essentially, at the nanoscale everything is sticky," Jones said. "When you put a large, flat particle on a large, flat surface, there's a lot of contact, and it's enough to permanently deform a particle that's really thin and flexible."

In the new study, the Rice team decided to see if this force could be used to manipulate 8nm-thick sheets of ductile silver. After a mathematical model suggested it was possible, the researchers placed 15nm-wide iron oxide nanospheres on a surface and then sprinkled prism-shaped nanosheets over them.

Without applying any other force, they saw through a transmission electron microscope that the nanosheets acquired permanent bumps where none existed before, right on top of the spheres. As measured, the distortions were about 10 times larger than the width of the spheres.

These hills weren't very high, but simulations confirmed that van der Waals attraction between the sheet and the substrate surrounding the spheres was sufficient to influence the plasticity of the silver sheet's crystalline atomic lattice. The researchers also showed that the same effect would occur in silicon dioxide and cadmium selenide nanosheets, and perhaps other compounds.

"We were trying to make really thin, large silver nanoplates and when we started taking images, we saw these strange, six-fold strain patterns, like flowers," said Jones, who earned a multiyear Packard Fellowship in 2018 to develop advanced microscopy techniques.

"It didn't make any sense, but we eventually figured out that it was a little ball of gunk that the plate was draped over, creating the strain," he said. "We didn't think anyone had investigated that, so we decided to have a look.

"What it comes down to is that when you make a particle really thin, it becomes really flexible, even if it's a rigid metal."

In further experiments, the researchers discovered that the nanospheres could be used to control the shape of the deformation, ranging from single ridges when two spheres are close together to saddle shapes or isolated bumps when the spheres are farther apart. They determined that sheets less than about 10nm thick and with aspect ratios of about 100 are most amenable to deformation.

In the paper, the researchers noted their technique creates "a new class of curvilinear structures based on substrate topography" that "would be difficult to generate lithographically". That opens up new possibilities for electromagnetic devices that are especially relevant to nanophotonic research. Straining the silver lattice could also turn the inert metal into a possible catalyst, by creating defects where chemical reactions can happen.

"This gets exciting because now most people make these kinds of metamaterials through lithography," Jones said. "That's a really powerful tool, but once you've used that to pattern your metal, you can never change it.

"Now we have the option, perhaps someday, to build a material that has one set of properties and then change it by deforming it. Because the forces required to do so are so small, we hope to find a way to toggle between the two."

This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

Republished by Plato

Published

on


A transmission electron microscope image by Rice University scientists shows a silver nanosheet deformed by a particle, which forms flower-shaped stress contours in the nanosheet that indicate a bump. Image: The Jones Lab/Rice University.
A transmission electron microscope image by Rice University scientists shows a silver nanosheet deformed by a particle, which forms flower-shaped stress contours in the nanosheet that indicate a bump. Image: The Jones Lab/Rice University.

New research has revealed that the hills are alive with the force of van der Walls. Researchers at Rice University have found that nature’s ubiquitous ‘weak’ force is sufficient to indent rigid nanosheets, extending their potential for use in nanoscale optics or catalytic systems.

Changing the shape of nanoscale particles changes their electromagnetic properties, said Matt Jones, an assistant professor of chemistry and an assistant professor of materials science and nanoengineering at Rice University. That makes the phenomenon worth further study.

“People care about particle shape, because the shape changes its optical properties,” Jones said. “This is a totally novel way of changing the shape of a particle.” He and his colleagues report their work in a paper in Nano Letters.

Van der Waals is a weak force that allows neutral molecules to attract one another through randomly fluctuating dipoles, or separated opposite charges, depending on distance. Though small, its effects can be seen in the macro world, like when geckos walk up walls.

“Van der Waals forces are everywhere and, essentially, at the nanoscale everything is sticky,” Jones said. “When you put a large, flat particle on a large, flat surface, there’s a lot of contact, and it’s enough to permanently deform a particle that’s really thin and flexible.”

In the new study, the Rice team decided to see if this force could be used to manipulate 8nm-thick sheets of ductile silver. After a mathematical model suggested it was possible, the researchers placed 15nm-wide iron oxide nanospheres on a surface and then sprinkled prism-shaped nanosheets over them.

Without applying any other force, they saw through a transmission electron microscope that the nanosheets acquired permanent bumps where none existed before, right on top of the spheres. As measured, the distortions were about 10 times larger than the width of the spheres.

These hills weren’t very high, but simulations confirmed that van der Waals attraction between the sheet and the substrate surrounding the spheres was sufficient to influence the plasticity of the silver sheet’s crystalline atomic lattice. The researchers also showed that the same effect would occur in silicon dioxide and cadmium selenide nanosheets, and perhaps other compounds.

“We were trying to make really thin, large silver nanoplates and when we started taking images, we saw these strange, six-fold strain patterns, like flowers,” said Jones, who earned a multiyear Packard Fellowship in 2018 to develop advanced microscopy techniques.

“It didn’t make any sense, but we eventually figured out that it was a little ball of gunk that the plate was draped over, creating the strain,” he said. “We didn’t think anyone had investigated that, so we decided to have a look.

“What it comes down to is that when you make a particle really thin, it becomes really flexible, even if it’s a rigid metal.”

In further experiments, the researchers discovered that the nanospheres could be used to control the shape of the deformation, ranging from single ridges when two spheres are close together to saddle shapes or isolated bumps when the spheres are farther apart. They determined that sheets less than about 10nm thick and with aspect ratios of about 100 are most amenable to deformation.

In the paper, the researchers noted their technique creates “a new class of curvilinear structures based on substrate topography” that “would be difficult to generate lithographically”. That opens up new possibilities for electromagnetic devices that are especially relevant to nanophotonic research. Straining the silver lattice could also turn the inert metal into a possible catalyst, by creating defects where chemical reactions can happen.

“This gets exciting because now most people make these kinds of metamaterials through lithography,” Jones said. “That’s a really powerful tool, but once you’ve used that to pattern your metal, you can never change it.

“Now we have the option, perhaps someday, to build a material that has one set of properties and then change it by deforming it. Because the forces required to do so are so small, we hope to find a way to toggle between the two.”

This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

Source: https://www.materialstoday.com/nanomaterials/news/weak-force-impact-metal-nanosheets/

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Material Science

Glass forming by metallic mixtures becomes clearer


Researchers at the University of Tokyo used computer simulations to model the effects of elemental composition on the glass-forming ability of metallic mixtures. Image: Institute of Industrial Science, the University of Tokyo.
Researchers at the University of Tokyo used computer simulations to model the effects of elemental composition on the glass-forming ability of metallic mixtures. Image: Institute of Industrial Science, the University of Tokyo.

Researchers from the Institute of Industrial Science at the University of Tokyo in Japan have used molecular dynamics calculations to simulate the glass-forming ability of metallic mixtures. They show that even small changes in composition can strongly influence the likelihood that a material will assume a crystalline versus a glassy state upon cooling. This work, reported in a paper in Science Advances, may lead to a universal theory of glass formation and cheaper, more resilient, electroconductive glasses.

Although a table might be set with expensive 'crystal' glasses, crystal and glass are actually two very different states that liquids, including liquid metals, can assume as they cool. A crystal has a defined three-dimensional lattice structure that repeats indefinitely, while glass is an amorphous solid that lacks long-range ordering.

Current theories of glass formation cannot accurately predict which metallic mixtures will 'vitrify' to form a glass and which will crystallize. A better, more comprehensive understanding of glass formation would be a great help when designing new recipes for mechanically tough, electrically conductive materials.

Now, researchers at the University of Tokyo have used computer simulations of three prototypical metallic systems to study the process of glass formation. "We found that the ability for a multi-component system to form a crystal, as opposed to a glass, can be disrupted by slight modifications to the composition," says first author Yuan-Chao Hu.

Stated simply, glass formation is the consequence of a material avoiding crystallization as it cools. This locks the atoms into a 'frozen' state before they can organize themselves into their energy-minimizing pattern. The researchers' simulations showed that a critical factor determining the rate of crystallization was the liquid-crystal interface energy.

The researchers also found that changes in elemental composition can lead to local atomic orderings that frustrate the process of crystallization, because these orderings are incompatible with the crystal's usual form. Specifically, these structures can prevent tiny crystals from acting as 'seeds' that nucleate the growth of ordered regions in the sample. In contrast with previous explanations, the scientists determined that the chemical potential difference between the liquid and crystal phases has only a small effect on glass formation.

"This work represents a significant advancement in our understanding of the fundamental physical mechanism of vitrification," says senior author Hajime Tanaka. "The results of this project may also help glass manufacturers design new multi-component systems that have certain desired properties, such as resilience, toughness and electroconductivity."

This story is adapted from material from the University of Tokyo, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

Republished by Plato

Published

on


Researchers at the University of Tokyo used computer simulations to model the effects of elemental composition on the glass-forming ability of metallic mixtures. Image: Institute of Industrial Science, the University of Tokyo.
Researchers at the University of Tokyo used computer simulations to model the effects of elemental composition on the glass-forming ability of metallic mixtures. Image: Institute of Industrial Science, the University of Tokyo.

Researchers from the Institute of Industrial Science at the University of Tokyo in Japan have used molecular dynamics calculations to simulate the glass-forming ability of metallic mixtures. They show that even small changes in composition can strongly influence the likelihood that a material will assume a crystalline versus a glassy state upon cooling. This work, reported in a paper in Science Advances, may lead to a universal theory of glass formation and cheaper, more resilient, electroconductive glasses.

Although a table might be set with expensive ‘crystal’ glasses, crystal and glass are actually two very different states that liquids, including liquid metals, can assume as they cool. A crystal has a defined three-dimensional lattice structure that repeats indefinitely, while glass is an amorphous solid that lacks long-range ordering.

Current theories of glass formation cannot accurately predict which metallic mixtures will ‘vitrify’ to form a glass and which will crystallize. A better, more comprehensive understanding of glass formation would be a great help when designing new recipes for mechanically tough, electrically conductive materials.

Now, researchers at the University of Tokyo have used computer simulations of three prototypical metallic systems to study the process of glass formation. “We found that the ability for a multi-component system to form a crystal, as opposed to a glass, can be disrupted by slight modifications to the composition,” says first author Yuan-Chao Hu.

Stated simply, glass formation is the consequence of a material avoiding crystallization as it cools. This locks the atoms into a ‘frozen’ state before they can organize themselves into their energy-minimizing pattern. The researchers’ simulations showed that a critical factor determining the rate of crystallization was the liquid-crystal interface energy.

The researchers also found that changes in elemental composition can lead to local atomic orderings that frustrate the process of crystallization, because these orderings are incompatible with the crystal’s usual form. Specifically, these structures can prevent tiny crystals from acting as ‘seeds’ that nucleate the growth of ordered regions in the sample. In contrast with previous explanations, the scientists determined that the chemical potential difference between the liquid and crystal phases has only a small effect on glass formation.

“This work represents a significant advancement in our understanding of the fundamental physical mechanism of vitrification,” says senior author Hajime Tanaka. “The results of this project may also help glass manufacturers design new multi-component systems that have certain desired properties, such as resilience, toughness and electroconductivity.”

This story is adapted from material from the University of Tokyo, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

Source: https://www.materialstoday.com/amorphous/news/glass-forming-by-metallic-mixtures-becomes-clearer/

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Material Science

Material Science News | Materials Research

Scintacor: An Overview of Its Products and Capabilities

In this interview, AZoM talks to Ed Bullard and Martin Lewis, CEO and Principal Engineer at Scintacor respectively, about Scintacor, the companies products, capabilities, and vision for the future.

Republished by Plato

Published

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Scintacor: An Overview of Its Products and Capabilities

In this interview, AZoM talks to Ed Bullard and Martin Lewis, CEO and Principal Engineer at Scintacor respectively, about Scintacor, the companies products, capabilities, and vision for the future.

Source: https://www.azom.com/materials-news-index.aspx

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