Symposium EP13: Thermoelectrics—Materials, Methods and Devices

Hyejeong Lee, Gwangju Institute of Science and Technology

Enhanced Thermoelectric Performance of PEDOT:PSS Nanotubes via AAO Template-Assisted Growth

Written by Bharati Neelamraju

Hyejeong Lee works with Ji Young Jo on using variations of PEDOT:PSS for thermoelectric applications. Lee addressed how conducting polymers are a good choice for wearable thermoelectric devices like thermoelectric generators (TEG). She said PEDOT:PSS is one of the highest conductivity polymers but that it still suffers from low thermoelectric efficiencies compared to their inorganic counterparts. The researchers fabricated PEDOT:PSS nanotubes in a template for enhanced thermoelectric efficiencies. They saw an increase in electrical conductivity due to the stretching of PEDOT chains as well as the decrease in thermal conductivity through phonon scattering in these nanotubes made in their laboratory. They achieved better efficiencies by adding post processing treatments and adding a solvent to these thin films. Lee concluded her talk by explaining to the audience why heading toward low-dimensional nanotubes is an interesting path forward for these materials.


Materials Needs for Energy Sustainability by 2050—Incentivizing a Zero-Waste Future

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Moderator: Elizabeth A. Kócs, University of Illinois at Chicago

Panelists:

  • Gabrielle Gaustad, Alfred University
  • Lucas Mariacher, Phoenix Public Works Department
  • Karsten Schischke, Fraunhofer Institute for Reliability and Microintegration

Written by Aashutosh Mistry

Population growth intrinsically strains resources supporting human life. The glocal (global and local) nature of today’s communities, combined with population growth, causes sustainability issues. Two separate paradigms have been advocated to assist sustainability goals: Materials for Sustainable Development (e.g., photovoltaics) and more recently Sustainable Development of Materials—a broader approach that promotes materials based on both application as well as sustainability. Despite the recognition of sustainability, waste management has been historically underappreciated, with most of the efforts contained in a linear system that either incinerates the final product or disposes it to landfills.

A panel discussion was organized around sustainability and waste management on Tuesday evening. It was argued that zero waste is a lofty goal, and the end effects may not be apparent immediately. Zero waste is difficult to achieve through waste management, and attention should be focused on waste prevention. Ensuring zero waste is a tricky balance due to a variety of often negatively correlated factors such as the interconnected nature of a zero waste economy, technological as well as policy challenges, the participation of producer and consumer, and different local standards to name a few. Additional ambiguity arises from the fact that zero waste is not consistently defined. For example, San Francisco, California enforces participation in recycling, in contrast to Phoenix, Arizona where it is voluntary. Circular economy, where materials are designed to be reutilized at the end of product life, creates problems as well, especially when a material is banned, and it needs to be phased out from all the phases of the circular economy.

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The panelists agreed to a need for lucrative incentives to pursue recycling. Many times, rearranging the process sequence itself can be an effective incentive, for example, a large fraction of recycling cost is attributed to processing—sorting out different waste types, and it is economically more feasible to incentivize consumers to categorize trash than handling it at a recycling plant. This cost of sorting waste often decides whether recycling can be pursued and, in the presence of unacceptable overheads, incinerators or landfills are preferred.

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A unique aspect of this panel discussion was the interactive participation of the audience in the form of audience polling. It was argued that good policies go a long way in realizing the zero waste future. Good policies are to be built upon scientific rationale and statistical data, both of which require active participation from scientists and engineers.

This event was supported in part by NSF, MRS Focus on Sustainability, MRS Energy & Sustainability journal, and Symposium ES13.


Symposium SM01: Materials for Biological and Medical Applications

Sebastian Kollenda, University of Duisburg-Essen and Centre for Nanointegration Duisburg-Essen (CeNIDE)

A Biosensor on the Nanoscale—About the Fate of Functionalized Inorganic Nanoparticles in Living Cells

Written by Gargi Joshi

Due to the natural occurrence of calcium phosphate in bones and teeth, nanoparticles based on calcium phosphate are being considered as a biocompatible option for drug delivery applications to carry cargo molecules like DNA, RNA, and proteins. In his talk, Sebastian Kollenda presented his recent results on therapeutic applications based on these nanoparticles in treatment of inflammation and derived carcinogenesis, vaccination against retroviral infections, as well as viral clearance. Moreover, the main goal was to monitor intracellular pathways and ejection from the body for such therapeutic nanoparticles. The particles have aspherical morphology, and were monodispersed with a typical diameter of 50–150 nm. Time-resolved CLSM demonstrated successful endocytosis of the particles loaded with protein into the cell which was found to be highly dependent on the localized pH values. Thus, a smart tool was designed by using a pH-responsive biosensor to efficiently visualize the intracellular pathways.


Symposium EP13: Thermoelectrics—Materials, Methods and Devices

Xavier Crispin, Linkoping University

Electronic and Ionic Thermoelectric Effects with Conducting Polymers

Written by Bharati Neelamraju

Organic thermoelectric materials are gaining traction for use as the power source for flexible wearable devices. Xavier Crispin talks about two kinds of thermoelectric charge carriers: hole and ion. His research group looks at both the electronic and ionic thermoelectric properties of these materials. Crispin showed how the time evolution of the thermo voltage between a pure hole transport, a pure ion transport, and then a mixed transport conductor is different with the mixed having the highest voltages. Ionic thermoelectric energy storage systems can be used such that it charges during the day due to a variation in temperature while it discharges in the night providing electricity. Polymer electrolytes that conduct ions have high Seebeck coefficients which makes them an ideal candidate for use in supercapacitors. However, these ionic polymer electrolytes are easily affected by humidity. Crispin’s group did a series of experiments to understand this humidity-dependence.


Symposium CP04: Interfacial Science and Engineering—Mechanics, Thermodynamics, Kinetics and Chemistry

Henri-Louis Girard, Massachusetts Institute of Technology

Waterbowls – Reducing Impacting Droplet Interactions by Momentum Reduction

Written by Aashutosh Mistry

Interactions of liquid drops and solid surfaces have been a classical problem in transport phenomena and extensively studied in various contexts such as heat, momentum, and mass exchanges. Depending on the application, one would want to either enhance the effective transport, for example, faster condensation on a colder solid (going from film-wise to drop-wise condensation) or attenuate the intrinsic characteristics of the solid–liquid pair, for example, icing of impacting drops on aircraft wings is detrimental and in turn reduced heat transfer is desired. The former problem of enhanced transport has received considerably more attention than the latter.

Henri-Louis Girard’s research focuses on the problem of attenuating the aforementioned transport modes. From a simplistic understanding, one could argue that liquid-repelling (e.g., hydrophobic for water-repelling) surfaces should provide reduced transport interactions. However, upon a closer look, Girard found that even if the hydrophobic surfaces do not let drops stick to the surface, the impact, oscillations, and rebound transients provide a thorough contact between the sold and flattened drop shape during the oscillation stage. In other words, both time of contact, as well as area of contact, contribute to effective transport. For a hydrophobic surface, the time of contact is smaller, but the contact area is fairly high which jointly leads to not so small interactions. Building upon this interpretation, the research group hypothesized that if the surface has circular ridges, the contact area can be reduced. Further experiments with varying circular ridge dimensions revealed three interaction regimes: (i) when the radius of the ring is smaller than that of the drop, upon drop impact it spreads over the ring and the ring cannot divert the momentum during spreading; (ii) when the radius of the ring is fairly higher than that of the drop (greater than three times), the effectiveness reduces as it does not divert the drop contact early on; and (iii) in between these two regimes, there is an interesting regime where the usefulness of the circular ridges deteriorates with an increase in their radii. At present, the researchers are analyzing the implications of an offset impact of the drop with such ridges in terms of momentum diversion and consequent attenuated transport interactions.


MRS Frontiers: Materials for Quantum, Biology, Sustainability, & Artificial Intelligence

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This 2019 MRS Spring Meeting featured a grandiose reception for attendees, concerning what would be the new topical areas of interest for future scientific meetings. While some seminal works in Quantum Information Technologies, Artificial Intelligence, Biomaterials (for example), and Materials for Sustainability have driven pop science intrigue, there is no doubt as to their research prominence, application, and concern for implementation based on where strategic materials advances could bring these fields into a more palatable reality.

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The networking reception itself was a very successful addition to the Meeting, collecting feedback and constructing working groups for where these topical areas are poised to inspire research presentations and publications, as well as secure collaborations for new research initiatives, grant applications, and establishing benchmarks for funding priorities.

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MRS, from grassroots initiatives of supporting higher level lobbying for initiatives pertinent to materials researchers, features political proceeds newsletters and the Materials Voice - a support feature for US constituents to e-mail their congressional representatives about specific policy concerns that are of vital importance to the materials research community. MRS, with the addition of other professional scientific organizations, features the National Photonics Initiative and National Quantum Initiative as a means for researchers to follow, at high level, the impending frontiers of research.

The MRS Frontiers Reception: Building Communities event was supported in part by ASU, ASM, LANL, ReACT, NSF, and Symposium ES13.


Symposium SMO1: Materials for Biological and Medical Applications

Fatemah Ostadhossein, University of Illinois at Urbana-Champaign

Oligodot Nanoparticles—A New Class of Fluorescent Nanoparticles for In Vitro and NIR In Vivo Imaging

Written by Gargi Joshi

Imaging techniques are of paramount importance in screening and analysis of any disease/condition in the medical field. The introduction of optical imaging has opened a new avenue with intraoperative feedback along with real-time monitoring of the situation. Moreover, it is a safer option as no invasive laser diagnosis is involved. In the case of quantum dots, the size is small, and they are cleared from the body through the renal tract in a short span of time and this can be quite tedious. The issue of their undetermined levels of toxicity can be completely ignored. Fatemah Ostadhossein introduced “oligodots” in her talk, which are ultrasmall nanoparticles. The pathological investigation of biodistribution in rats showed no accumulation of these particles in the major organs like the heart, liver, or kidneys and proper window clearance of over 3 hours. Ostadhossein’s next aim is to expand the library of these particles.


Symposium EP01: Liquid Crystalline Properties, Self-Assembly and Molecular Order in Organic Semiconductors

Takashi Kato, The University of Tokyo

Nanostructured Liquid-Crystalline Assemblies for Ion and Electron Transport

Written by Bharati Neelamraju

Functional nanostructured liquid crystals are being used toward the next generation of materials for energy devices, especially lithium ion batteries, fuel cells, and dye-sensitized solar cells. Takashi Kato began his talk with a timeline of use of liquid crystals from 1889 to the current generation of liquid crystals. He talked about how it was after 1990 when materials science and chemistry became as interconnected as they are today. His group in the Department of Chemistry and Biochemistry works on creating a variety of molecular structure of liquid crystals for ion conductive electrolytes that can be used in lithium ion batteries. He covered varying nanostructures of liquid crystals with varying functionality and ionic transport directions (1D -2D- 3D). Liquid crystals have nanoscale self-organization, homogenous domain, and a dynamic phase nature which makes them an interesting material for conductive electrolytes which can also be used in electrochromic windows. The research group focused on creating approaches to increase conductivity and design materials with better alignment for ionic transport between electrolyte and electrode. Kato showed with an example that these ionic liquid crystals have a switching behavior wherein the nanostructure goes from rectangular to hexagonal by application of heat. This switch in nanostructure makes the liquid crystal conductive from a non-conductive state.


ES04: Solid-State Electrochemical Energy Storage

Nancy Dudney, Oak Ridge National Laboratory

Growth and Properties of Lithium Thin Films for Solid State Batteries

Written by Aashutosh Mistry

A curse of lithium-based batteries is the inability to use bare lithium as an electrode material. In a conventional setting, when lithium thin film electrodes are used, they give rise to nonuniform evolution upon repeated deposition–dissolution as the cells are cycled. The polycrystallinity of the as available lithium films makes for preferential nucleation based on the grain structure.

Following up on this reasoning, Nancy Dudney and her colleagues hypothesized electrochemically generating lithium anode in situ. In such an instance, they assemble cells with a current collector on one end and lithiated cathode on the other. The first step involves electrochemically delithiating the cathode to reconstruct the lithium anode on the current collector. Such an approach gives rise to a very different crystal structure for the recovered lithium anode and in turn a very distinct electrochemical behavior. The researchers could operate such a cell for more than 10k cycles (quite greater than using as received lithium anodes).

Upon further probing of the lithium–electrolyte interface, the researchers observed many interesting features. First, they found lithium to redistribute upon cycling, in that, it does not always come back to the same configuration. Such a redistribution appears to be a function of the specific cathode material as well as the cycling characteristics. For example, redistribution occurred earlier with a lithium manganese oxide as compared to a lithium cobalt oxide cathode. These findings point to a previously unexplored correlation between grain structure of lithium thin films and their electrochemical response.


Symposium QN01/QN02/QN03: Keynote: Joint Session: Materials Science with Two-Dimensional Atomic Layers

Pulickel Ajayan, Rice University

Materials Science with Two-Dimensional Atomic Layers

Written by Chiung-Wei Huang

Graphene and associated two-dimensional materials are the new types of building blocks of electronics. The layered compounds with their unique properties have fascinated scientists for many years. In the keynote session, Pulickel Ajayan systematically reviewed the synthesis, characterization, doping, and manipulation of the 2D materials realm. He started the presentation with exfoliation methods in producing thin-layered 2D materials such as tellurene and magnetene. Ajayan followed with functionalization approaches, such as Cu atoms intercalation and liquid phase assisted quantum dots production. One of the newest materials reported earlier this month involved a high elasticity graphene foam that persists to deeply low temperature.

The second part of the session dived into manipulating the interfacial structures to give the best control of growing these materials. Ajayan overviewed the electronics engineering on multicomponent alloys of 2D materials methods and the associated challenges. He closed his talk by pointing out the urgent understanding into the phase stabilities, segregation, and mechanical properties of these novel materials.