The Materials Research Society held its Spring Meeting on April 17-21 in Phoenix, Arizona. See the highlights reported on social media by participants, presenters, and others as well as reports from additional MRS news sources.
David Prendergast, Lawrence Berkeley National Laboratory
Understanding the Nature of Chemical and Electrochemical Stability of Electrolytes at Mg Anode Surfaces
Written by Aashutosh Mistry
With depleting reserves for lithium, there has been an active interest in making successful secondary batteries using other alkali and alkaline metals. Magnesium is one of the competitors, given reasonably smaller size and high but not extreme reactivity (making it safer). In addition, experimentally no dendrites are observed on magnesium surfaces, in contrast to lithium metal where dendrite-free electrodeposition is more of a dream than reality.
There are two long-standing problems with Mg—unavailability of a good cathode host and search of a suitable electrolyte that would lead to desired Mg/electrolyte interface. David Prendergast of Lawrence Berkeley National Laboratory and his colleagues have been investigating the science of the Mg/electrolyte interface using a three-pronged approach that involves Ab initio molecular dynamics (AIMD) simulations, x-ray spectral interpretation of in situ chemical/electrochemical tests and condensed phase interfacial modeling. The research question addressed in this talk was whether a combination of good electrode (Mg) and good electrolyte would lead to a good interface, and possibly an interphase as well. They experimented with Mg symmetric cells using Mg(AlCl2BuEt)2 salt in tetrahydrofuran (THF) electrolyte. They found out that even under no electrochemical bias (i.e., open circuit situation), there is a formation of different magnesium compounds on the electrode surface—for example, oxides MgO, hydroxides Mg(OH)2, and carbonate MgCO3. From molecular simulations, the researchers revealed that such reactions are only possible given surface defects on the electrode and which can subsequently lead to electrolyte decomposition. At this stage, they are involved in further electrochemical testing and equivalent modeling. The overall study is of extreme importance and should help identify suitable materials for Mg battery.
Andres Vasquez Quintero, Ghent University
Fabrication of Fixed-Shape Soft Smart Objects by Thermoplastic Forming of Flat Stretchable Circuits
Written by Akshay Phadnis
An increasing interest in stretchable, controlled shape polymer has inspired Andres Vasquez Quintero of Ghent University to develop shape-retaining electronic circuits. These circuits are based on elastic circuits with substitution by thermoplastic polymer carrier. Most importantly, these circuit systems are supposed to take a predetermined shape in the absence of any external force, for example, smart lenses (to replace the bi-focal glasses) or shoe in-soles. A flexible electronic circuit capable of stretching and deforming is first developed and then molded into the desired shape using a thermoforming process using suitable molds. Smart lenses developed using this methodology were demonstrated. Various challenges faced in the development of these lenses such as wrinkling were discussed in detail. These dynamic lenses can be tuned to be adaptable to environmental condition using LCD monitors to develop tunable lenses.
Kenneth C. Manning, Arizona State University
Super-absorbing Polymers for Breathable and Self-Sealing Smart Hazmat Suits
Written by Akshay Phadnis
Superabsorbent polymers are a special class of stimuli-sensitive polymers that undergo multifold swelling upon contact with the suitable solvents. Kenneth C. Manning of Arizona State University proposes to use such polymers in developing breathable, self-cleaning hazmat suits for use in chemically hazardous environments. If the polymer is tuned to be swelling when in contact with these chemicals, the swelling property of the polymers can be utilized to reduce the permeability of the chemicals. Since the suits will be “breathable” at all other times, there is no need of separate cooling mechanics to regulate the body temperature, which otherwise is needed in the case of current hazmat suits. The swelling phenomenon of the polymer is characterized experimentally in terms of swelling ratio, swelling time, and repeatability for selected choice of solvents. A finite element-based mathematical model is also implemented to represent the swelling. Using this model, various configurational studies can be done to design the shape and size of the polymer matrix. Also, since these polymers need to be combined with the wearable suits, an optimized method to develop a polymer-fiber matrix can be designed using this model. Use of this selective, self-breathable hazmat suit will bring a new future to the hazmat suits in chemical warfare.
Chong-Yu Ruan, Michigan State University
In situ imaging of complex phase transitions in functional transition metal compounds at ultrafast timescales
Written by Trevor Clark
In high speed imaging only a small amount of the light/electron information can be captured. A high intensity brightness is required to be able to distinguish what is in the image. This is easy enough to do for light imaging by just adding more photons; however, it is not as simple for electrons: if packed into high densities their charges repel each other resulting in greatly reduced spatial resolution. This space-charge effect can be corrected by radio frequency (RF) longitudinal lenses, and allows for the capability of imaging extremely fast processes. These RF cavities allow for correction of temporal and spatial anomalies by changing the high-volume electron flow from turbulent to laminar. This retains benefits of increased brightness from increased dose, while limiting the negative resolution impacts from the space-charge effect. This lens setup has been used to study the ultrafast phase transitions in transition metal dichalcogenide systems, and is a promising tool for advanced materials characterization at the ultrafast time scale.
Khalid Hattar, Sandia National Laboratories, Boise, Idaho
In situ Ion Irradiation Dynamic TEM
Written by Trevor Clark
Understanding radiation effects at a microstructural level is important on many scales. A microchip in close proximity to a nuclear reactor needs to be very reliable and components on spacecraft also have the need for reliability. Khalid Hattar of Sandia National Laboratories in Boise, Idaho is working with industry to develop setups to allow for radiation sources within a transmission electron microscope (TEM) to dynamically, in real time, view the effects of radiation on the microstructure at the nanometer scale. The radiation is ionic gold particles that are accelerated to high speeds within the machine; this means that the particle–material interactions can occur at very short time scales, on the order of 10–100s of nanoseconds. Hattar and his team have made many optimizations to retain the high spatial resolution, tune the radiation to single particle events, and have a high time resolution. The camera and detectors are optimized for stability and resolution. This set up allows for many in situ TEM experiments that will offer much needed insight into a variety of nanoscale processes.
The five-day meeting has brought me a lot.
1) Deepened my understanding about my research through presentations and discussions with researchers with different backgrounds but working in fields relevant to my research.
2) Practiced how to present and communicate effectively to both experts in my fields and "laymen" with other research specialty.
3) Practiced scientific writing and news writing by attending the MRS Science Writing workshop and serving as a blogger.
4) Extended my professional network. I've interviewed leading figures in my research fields and was also able to discuss with other talented graduate students.
5) Met MRS organizers who I would never see in my life if I didn't decide to come. Chats with session organizers and meeting organizers as well as MRS website administrator revealed numerous behind-the-scenes stories, adding unique elements to my meeting experience.
If you are one of the graduate students who are reading this post but didn't get a chance to involve this time, I would encourage you to attend the MRS Fall Meeting at Boston in this Nov.
-Ingrid
I am ready to bring what I had learned about my materials and processes back home with me to the lab. MRS may be over for now, but the effects that this conference had will play a vital role in my research. -Ingrid
Ever since I saw Pizzeria Bianco on Yelp I knew I had to visit the cute little red brick building once before I leave, and today seemed like the perfect opportunity to do so. With the one hour I had left in Phoenix, before my flight back to Los Angeles, I made my colleagues walk over to Heritage Square to grab a pie with me. Because it was after lunch hours there was no wait at all for a table, but the restaurant was still pretty and almost full.
I ended up ordering a 1/2 Sonny 1/2 Wiseguy pizza, while my colleague enjoyed a unique gingerale (this soda brand that Pizzeria Bianco carried boasts low sugar as a feature). The pizza was amazing and words can't do justice, but I can guarantee that the somewhat steep price of $20 for a small pie was worth all my dollar bills. If you're in the area and/or looking for a great pizza, stop by Pizzeria Bianco.
The convention center, my home for the last week, is a unique building. Perhaps my favorite architectural quality of the convention center would be the giant “garage door” which opens during the mornings. It makes the PCC very accessible and open to the world around it. It made the atmosphere of the convention extend beyond the heavy (they were pretty heavy for me) doors, and out to the streets, to fully embrace the city.
Going downstairs to the exhibit hall and registration was a complete transformation as well, seeing high ceilings and large open areas, even allowing for indoor walking between PCC buildings. Being on the first floor, PCC West was a very busy place where I saw most of my nanomaterials talks. PCC North seemed to be a bit calmer. The rooms in North seemed much larger, and more personal.
While the PCC is not the biggest convention center I’ve been in, it definitely has a lot of character to it. I think this was a great choice for MRS17 to have been held.
-Ingrid