Special message for #s19mrs

The 2019 Materials Research Society Spring Meeting & Exhibit, in Phoenix, Arizona is being held on April 22-26, 2019 with 59 symposia and several tutorialsprofessional development seminars, information on accessing National Laboratory User Facilitiesoutreach opportunities, and numerous other activities and events. Award presentations include studies in catalysis, nanomaterials, and bioelectronics; and the plenary session features the Fred Kavli Distinguished Lectureship in Materials Science.

Many exhibitors will feature products and services at the Meeting. Exhibit hours are Tuesday, 2:00-7:00 pm and Wednesday, 11:00 am-7:00 pm, in the North Building of the Phoenix Convention Center, 300 Level, Halls C-E.

The Meeting App is available to help schedule your activities.

During the meeting, MRS will post news and highlights by on-the-spot reporters on this Meeting Scene blog. The news will also be distributed daily in the Meeting Scene newslettersubscribe here.

ALSO - Share your experiences at #s19mrs!

S19 Phoenix

2018 MRS FALL MEETING: Symposium BM08: Materials-to-Devices for Integrated Wearable Systems—Energy Harvesting and Storage, Sensors/Actuators and Integration

Svetlana Boriskina, Massachusetts Institute of Technology

Wearable Fabrics for Passive Heating and Cooling - Can Polyethylene Do Both?

Written by Daniel Gregory

Fabrics provide a key additional layer that helps to regulate human body heat. In extreme environments, current clothing options are typically either very bulky, cool passively using moisture wicking from sweat, or have poorly integrated elaborate active cooling systems. Svetlana Boriskina explored the ability of polyethylene to provide both active and passive cooling effects. Polyethylene was chosen due to its low absorption of near-infrared wavelengths, emitted for radiative cooling in humans. Other textile fabrics usually absorb strongly in this region, and so are unable to let heat escape to cool properly, or reflect the heat back to the wearer, though metals can be added for this reflection.

The challenge with polyethylene is to make it visible in the near infrared yet opaque at visible wavelengths. To do this, Boriskina explained how she and her group were able to create fibers with diameters roughly equal to the wavelength of visible light but thinner than infrared radiation, causing a scattering effect that provided the visible light opacity. This was further demonstrated through infrared and visible camera comparisons. Polyethylene processed in several different ways was then compared to metallized emergency blankets and unprotected bare skin analogue in their ability to insulate heat given off by a surface and also keep that surface cool under sunlight. It was shown that powerful heating or cooling effects depended on the processing method, with knitted polyethylene outperforming the emergency blanket in thermal insulation while nanoporous polyethylene was the most effective cooling fabric, and showed promise as a material for thermal camouflage. Boriskina presented tests of moisture wicking and drying time, showing surprisingly that knitted polyethyelene performed best despite the polymer usually being hydrophobic. The material was also shown to have many other properties such as its light weight and the ability to be processed into fabric on conventional equipment and in a range of colors, as well as already having a well-established recycling procedure.

Symposium NM01: Carbon Nanotubes, Graphenes, and Related Nanostructures

Michael Strano, Massachusetts Institute of Technology

From Energy Harvesting to Living Plants—Concepts in Biosensing and Energy Conversion Using Carbon Nanomaterials

Written by Daniel Gregory

As he presented an expansive variety of ideas currently under research, Michael Strano provided an excellent example of how modular and customizable nanomaterials can be. He began his talk with work on transitioning the extraordinary mechanical properties of carbon nanotubes and graphene into macroscopic materials. This was achieved by growing graphene from chemical vapor deposition on a substrate, then rolling or folding the substrate into a fiber or sheet, respectively. By doing this, Strano and his group were able to extend reinforcement throughout the dimensions of their material, greatly improving the reinforcement of the composite while reducing the volume fraction. Following this was a brief explanation of a thermal resonator, using the thermal effusivity of carbon nanomaterials to make a device capable of generating power from temperature fluctuations in ambient conditions. The talk moved swiftly on to the properties of nanoconfined water, using temporal Raman spectroscopy to observe fluids moving through nanotubes. The group was able to confirm previously described theoretical predictions and experimentally expand the understanding of highly distorted fluids. Pivoting, Strano gave a detailed description of his group’s ability to embed readable and writable circuits in colloidal nanoparticles using two different methods. After talking briefly about near-infrared fluorescent single-walled nanotubes and their applications in individual protein sensing, Strano concluded with a description of how nanotube-wrapped DNA molecules were shown to penetrate previously impenetrable membranes in plants, such as the chloroplast membrane. After developing models and equations to describe this motion, Strano finished with some intriguing applications in chemical sensing and bioluminescence.  

Symposium BM07: Bioelectronics—Fundamentals, Materials and Devices

Brian Litt, Penn Epilepsy Center

 Engineering the Next Generation of Neurodevices—New Materials and Clinical Translation

Written by Hortense Le Ferrand

Innovation in materials science can help clinicians in many ways. As an example, Brian Litt from the Penn Epilepsy Center introduced the case of an epileptic patient suffering from regular seizures. By implanting four electrodes into the brain of the patient, the clinicians could determine where abnormal activity occurs and locally ablate those areas. This is the technology used to treat epilepsy for the past 20 years and still used today. As a result, the patient had less intense seizures, but still some epileptic symptoms remain.

Litt described several areas where materials researchers can work together with medical doctors to improve the therapy and treat the patient. First, decreasing the size of the electrodes and improving their biocompatibility would reduce the inflammatory response post-implantation and the tissue damage. Second, increasing the number of electrodes to a reasonable amount could allow a more accurate detection of the epileptic network location. Third, development of a cloud-based system to collect, compute, and interpret the data from the electrodes is also needed.

If there is a lot of progress and innovation in the fabrication of multiple channels electrodes and biocompatible materials, there is still a significant gap between the research and the concrete applications. Litt emphasizes with this example the need for collaborations to achieve translational applications.

Symposium BM08: Materials-to-Devices for Integrated Wearable Systems—Energy Harvesting and Storage, Sensors/Actuators and Integration

Philipp Simmons, Massachusetts Institute of Technology

All-Solid-State Glucose Fuel Cell for Energy Harvesting in the Human Body

Written by Daniel Gregory

Wearable devices and implants within the human body require a reliable source of power. Fuel cells operating through the oxidation of glucose to gluconic acid are an attractive option; however, current devices predominantly use polymer membranes or liquid electrolytes to separate the membranes. This leads to immense challenges with rapid degradation, unpredictability, and an inability to miniaturize the system, leading to insufficient power density. Philipp Simmons introduced an all solid-state glucose fuel cell using a solid ceria membrane and a porous platinum catalyst. The materials are all biocompatible and provide a high power density, and the device is fabricated on silicon for easy integration to other devices.

A key challenge when fabricating these devices was the mechanical stress imposed by the pulsed laser deposition (PLD) of the ceria. By lowering the background pressure in the PLD system, Simmons found that the microstructure of the ceria changed, with grain sizes increasing as the film grew away from the silicon substrate, reducing strain. The novel microstructure also improved device performance due to the ceria now becoming nanoporous. Simmons then explained the mechanism of proton transport in ceria and the way in which the device was able to confirm this, before concluding with a detailed presentation of the device performance. Of note was the high current density even in unengineered devices, and a record high cell potential nearly triple current literature values. More work is being done by the group to determine the causes for this and further optimize the device performance.

Science Communication—Reaching the Public

The Eigenprot is a musical instrument based on the molecular vibrations of 100,000 protein structures. When asked the purpose for this, Markus Buehler of the Massachusetts Institute of Technology said to provide an opportunity for the public to interact with materials at the nanoscale. Buehler described this work in the symposium cluster on Broader Impact (Symposia BI01 and BI02). The sound, he said, generates from many overlaying vibrations of the protein molecules, which is analogous to a guitar string. For educational outreach, participants can learn a parallel in terms of hierarchy: music begins with notes, which can advance into a melody, and further into harmony. Similarly, materials begin with an atom, then another atom can be added to it, the grains, and so on. Another application of this new tool can be to understand how mutations or misfolding as seen in many diseases lead to differences in a protein’s vibrations, and how this translates to audible sound. Such studies can offer a new tool, in the lab, to understand molecular defects in a totally different domain, for further analysis.

In an outreach setting, participants would be able to interact with the protein synthesizer in order to create their own sound combination. Here is the sound generated based on PDB ID 101m, playing a C2 note for several bars. This one is generated based on PDB ID 4yz2, playing a C1 note for several bars.

For contrast, here is a simple composition created using three copies of the protein synthesizer (each playing a distinct melody or chord progression), along with a TR-808 drum loop for texture:

Graduate students at Arizona State University launched their own effort in reaching a general audience with a different sound: their podcast, called podQESST. Sebastian Husein said their goal is to present what scientists do in a storytelling format in order to engage their listeners.

Julie Nucci of Cornell University also champions storytelling in order to reach the general public. She introduced a course where students utilize a padcaster—the video recording feature on an iPad—to produce interesting engineering features. The engineering students practice three points in their storytelling efforts: show what you are doing, make it personal, and show why the world cares. While subscribing to these three points may sound easy, it actually takes a lot of practice.

Wind-up toyIn a Science Communication Workshop held on Sunday, prior to the symposium sessions, Daniel Steinberg and Sara Rodriguez of Princeton University provided ample time for participants to practice communicating their work. The workshop was designed to help researchers to increase their confidence in communicating science to the nonspecialist. One of the activities let the researchers experience the “other side” of the dialogue: A spinning device was set before them—looking as strange to them as their lab work would look to a non-scientist. Putting the shoe on the other foot helps researchers understand what information they need to give.

The ability for materials researchers to reach the public has significance beyond “public outreach.” Mark Miodownik of University College London floated the necessity for materials researchers to consider working with experts in other fields in order to advance the complex materials of the 21st century, for example, self-healing concrete. In order to embrace complex solutions for sustainability, he said, materials researchers may need to work with designers and psychologists, for example; so the ability to communicate science with non-scientists becomes imperative.



Symposium EP03: Beyond-Graphene 2D Materials—Synthesis, Properties and Device Applications

Babak Anasori, Drexel University

Synthesis of 2D Metal Carbides and Nitrides (MXenes) and Their Applications

Written by Tianyu Liu

MXenes are a large family of two-dimensional transition metal carbides and nitrides. Since the synthesis of the first MXene, Ti3C2, in Drexel University, MXenes have been utilized in a diverse array of applications: electronics, optics, energy storage devices, and catalysts, for example. Babak Anasori from Drexel University overviewed MXenes from the angles of the history, synthesis strategies, processing methods, and new applications demonstrated in 2018. In addition, Anasori revealed that most MXenes, when dispersed in water, were spontaneously oxidized by dissolved oxygen gas. The oxidation decreases the dispersion stability and the electrical conductivity of MXenes. Effective methods to slowdown MXene oxidation include storing MXenes at temperatures below room temperature, enlarging the flake size of MXenes, and processing MXenes into dry films as well as dispersing MXenes in organic solvents. Anasori also discussed unresolved challenges pertaining to MXenes, including measuring the inter-flake electrical conductivity, synthesizing MXenes with functionality-free surfaces, and preparing MXene thin films with chemical or physical vapor deposition techniques.

Symposium GI01: Machine Learning and Data-Driven Materials Development and Design

Placidus Amama, Kansas State University

Industrial Waste Gas mixture as a feedstock in Efficient Carbon Nanotube Growth—Using an Autonomous Research System to Probe Growth Kinetics and Mechanisms

Written by Daniel Gregory

Aligned carbon nanotubes in “carpet” or “forest” arrays are highly desired in a range of applications, but require controlled properties and efficient production at large scale with low cost to meet this demand. Placidus Amama first explained the complexities of the Fischer-Tropsch synthesis method for liquid fuels, highlighting the inability to have 100% liquid fuel selectivity. From this, he described his group’s approach to the problem, wherein the gas phase of the synthesis could be combined with chemical vapor deposition to produce carbon nanotubes, alongside the liquid hydrocarbons. After showing favorable comparisons against other leading synthetic methods including carpet density, growth lifetime, and yield, Amama explained the group’s use of an autonomous research system (ARES) to optimize selected parameters. The system uses laser light to both heat the samples for chemical vapor deposition, and characterize them using Raman spectroscopy. A detailed description of the effect of heat and water content on yield was presented alongside microscopy characterizations of the optimized reaction conditions. Amama then briefly described the proposed mechanism for this reaction based on the collected data and some results from experiments changing the composition of the gas feedstock before concluding with future plans to use the ARES to further probe these compositional changes.

Symposium BM01: 3D Printing of Passive and Active Medical Devices

Michael Hausmann, EMPA and Swiss Federal Institute of Technology of Zürich

Rheology and Direct Ink Writing of Strong Cellulose Reinforced Composites

Written by Hortense Le Ferrand

Reinforcing polymeric matrices with nanoparticles is a common way to increase their mechanical properties. With the booming of the three-dimensional (3D) printing industry, there is a demand for printing parts that not only possess the benefits of 3D printing but that also perform mechanically well. Indeed, the polymers that are widely used in current printers are still weak and cannot be used in structural applications.

Cellulose nanocrystals (CNCs) are elongated nanoparticles issued from plant-based parts. CNCs align under shear to anisotropically reinforce matrices. In a direct-ink writing printing process, a viscous fluid is extruded through a nozzle and deposited on a substrate. The fluid therefore undergoes shear at the nozzle.

To develop cellulose-reinforced composites with specific mechanical properties, it is important to understand the response of CNCs under shear. For this purpose, Michael Hausmann and his colleagues performed in situ polarized rheology to directly track their dynamic orientation under shear at various concentrations. When the CNCs align, they behave like liquid crystals and display colors that are visible between cross polarizers. For example with 20 wt% of CNCs, no color is visible at low shear and the CNCs are randomly oriented, but above 200 Pa of shear stress, colors appear revealing the CNCs’ alignment. This phenomenon is observed for lower concentrations. However, above 25 wt%, the CNCs were never found to align, probably due to steric hindrance and collisions.

Since the shear profile at the tip of the nozzle of a 3D printer is well known, it is now possible to determine the conditions to realize local orientation of the CNCs in a printed part.

Symposium NM01: Carbon Nanotubes, Graphenes and Related Nanostructures

Motoyuki Karita, Shizuoka University

Structural Changes in Carbon Nanotube Yarn Exposed to Actual Space Environment

Written by Tianyu Liu

Have you dreamed of taking an elevator from Earth to the Universe for space traveling? This fictitious idea might come true. Materials researchers have proposed to use carbon nanotubes (CNTs) to make the elevator ropes, due to the excellent mechanical robustness of CNT. However, the high-energy radiations in the Universe might compromise the structural integrity of CNTs and, thus, the safety of the elevators. Motoyuki Karita from Shizuoka University, Japan, studied the degrading process of multiwalled CNTs when exposed to the actual space environment. The researchers attached a piece of CNT-yarn mat on the outside wall of an international space station, and monitored the structural change during two years. In the meantime, on Earth, Karita and co-workers performed comparison tests by irradiating three pieces of the same CNT mats with atomic oxygen (AO), electron beam, and ultraviolet light. The CNT mat in the space experienced significant deterioration in mechanical strength, similar to the AO-irradiation case performed on Earth. Karita’s study reveals that the atomic oxygen atoms are the most corrosive species to CNTs, and  protective coating of CNTs is indispensable to ensure the reliably of CNT-elevators.