The 2016 MRS Spring Meeting was held from March 28 – April 1 in Phoenix, Arizona. Recorded highlights include a number of sustainability-oriented talks, three tutorial sessions and more.
Aligned carbon nanotube (A-CNT) based polymer nanocomposites (PNC) are an important class of next-generation advanced materials. Due to the superior, uniaxial properties of the CNTs themselves, composites with tailored, anisotropic properties can be created. However, the experimentally-determined properties of such advanced PNCs, although much higher than the alternatives, still fall short of theoretical predictions. Recently, we have developed the ability to characterize the 3D morphology of such PNCs at the nanoscale using energy-filtered electron tomography. In this presentation, we discuss our novel imaging protocol and an automated segmentation methodology that enables the fast, accurate characterization of statistically-relevant volumes of low-contrast A-CNT PNCs. Further, we discuss image analysis schemes that aid in the extraction of rich, quantitative morphological data (alignment, bundle/network structure, 3D waviness) from the 3D reconstructions. We use this data to re-visit previously-performed experimental measurements of electrical, thermal and mechanical properties in these PNCs. The results show new trends in the dependence of these properties on the CNT volume fraction, and explain previously perplexing phenomena. We observe that the CNT-CNT network connections play a dominant role in transport properties such as electrical and thermal conductivities. Additionally, CNT waviness and proximity are found to strongly influence the PNC stiffness. Electron tomography is shown to be a powerful tool in establishing nanocomposite structure-property relations, making it an essential tool for understanding and tailoring the next generation of advanced materials.Speaker(s):
Many materials researchers strive to contribute to technologies that are more “sustainable” than ones we use today. Often, these efforts focus on improving resource efficiency by creating materials and devices that are less energy, water, and material intensive. But for more sustainable technologies to be commercially viable and have a global impact, there are additional considerations, including raw material availability, product lifetime, social and economic dimensions, and how best to balance adverse short-term impacts with potential long-term gains.
Instructors Tatiana Vakhitova and Alan Rae show how to incorporate sustainability principles into your research in a more comprehensive way while considering the real-world application of these principles to product design and manufacture. This seminar is aimed at materials researchers of all career stages, from students and postdocs to faculty and industry researchers.
Much Materials research today has, as its primary or one of its secondary aims, to contribute to the technologies that are more “sustainable” than those we now use. The immediate perception this creates is one of resource-efficiency: technology that is less energy intensive, less water intensive and less material intensive than at present. But if the claim of a sustainable development is to be justified, there are further considerations. Globally, the annual resource-consumption in question (energy, water, materials) are not measured in joules, ccs or grams but in petajoules, cubic kilometers, billions of tonnes. If the research material is to be “disruptive”, making a significant contribution to a more sustainable way of life, will have to be produced on a scale, and in a time-frame, that have a measureable effect on this consumption. If on this scale there are other consequences: markets are disturbed, people are affected - there are social and economic dimensions, when adverse short-term impacts may have to be justified by long-term gains. It is not the job of materials researchers to solve these problems but to be aware and if they are to make claims that their research has “sustainability” as a tag line, it would be responsible to survey how it might map-out on the larger scale.
The paper will focus on a methodology for thinking about this, starting from the proposed “sustainable development”, exploring the context: the nature of the innovation and the stakeholders that it involves
1. the material demands and the ability of the global supply chain to meet them;
2. the risks associated with a given material choice and ways of mitigating the risk by substitution;
3. the ultimate impact of the innovation on natural, manufactured, human and social capital.
Reversing combustion and recycling carbon dioxide and water back to liquid hydrocarbons is an attractive option for storing solar energy and mitigating the growth of atmospheric CO2 concentrations. For any such process, high solar-to-fuel efficiency, appropriate materials thermodynamics, kinetics and availability is critical for large scale viability and favorable economics. Redox active mixed perovskite metal oxide-based thermochemical approaches for solar-to-fuel have the potential to be highly efficient as they have a tunable parameter space, avoid inherent limitations of photosynthesis (biofuels), and sidestep the solar-to-electric conversion necessary for electrolytic reactions. This presentation highlights progress from multidisciplinary and international efforts that has been progressing down a technical path for systems, novel reactors, and materials design and discovery for making liquid hydrocarbon fuels from concentrated sunlight, waste carbon dioxide, and brackish water based on a two-step metal oxide redox cycle motivated to address the dual challenges posed by the strategic and economic importance of petroleum and the increasing concentration of atmospheric carbon dioxide. One take-away message will be that given high enough efficiency (> 10% on a lifecycle basis - sunlight to fuel) energy conversion routes, supplanting a large fraction of global petroleum-derived liquid fuels with synthetic solar-fuels, are challenging but nonetheless possible; indeed they are quite plausible with affordable economics.Speaker(s):
Renewable energy sources are unlikely to completely displace traditional thermal energy generating methods in the foreseeable future. Furthermore, renewables such as solar and wind power require traditional backup systems for windless and/or cloudy days. Consequently, finding routes to increase efficiency of traditional power generating approaches should be considered an integral part of sustainable development. This is not a simple task, since thermal power plants that operate on a steam cycle have been around and continually improved for over a hundred years. Finding routes to passively enhance steam condensation rate, which governs the back-pressure for the steam turbines, is one of the remaining materials-development opportunities in this area. Steam condensers are fundamental components of about 85% of electricity generation plants and 50% of desalination plants installed globally.1 Consequently finding routes to even moderately improve efficiency of the condensation process could have substantial impact on sustainable development.
In this talk we will provide a brief overview of steam condensation fundamentals and how novel materials can be used to enhance efficiency of this phase change process. Since the 1930s, hydrophobization of metal surfaces has been known to increase heat transfer during water condensation by up to an order of magnitude,2 whereby this surface modification switches the condensation mode from filmwise (FWC) to dropwise (DWC). However, use of hydrophobic coatings required to promote DWC introduces an additional resistance to heat flow. Thus, in simplified terms, to increase the total heat transfer rate, thermal resistance introduced by the hydrophobic coating must be significantly smaller than that posed by the water film during FWC. Unfortunately, most hydrophobic coatings suffer from longevity issues. We will review recent material developments in this area (rare earth oxides, grafted polymers, grapheme, and lubricant impregnated surfaces etc.) and durability challenges stemming from thin film nature of these hydrophobic coatings. We will also discuss our recent alternative to these thin film modifiers: metal matrix hydrophobic nanoparticle composites.3 We have recently demonstrated that with properly sized and distributed nanoparticles, such materials can sustainably promote DWC. Furthermore, due to the high thermal conductivity of the matrix, the composites have a potential to be used in bulk-like manner. This could dramatically enhance their longevity as compared to thin film hydrophobic promoters and thus provide a viable route of sustainably enhancing condenser, and with that power plant, efficiency.
Significant efforts have been made to advance technologies that provide a reduction in the energy demands of consumers. For instance, bulbs made with light emitting diodes (LEDs) have been demonstrated to last longer and save substantial energy when compare to conventional incandescent lighting. Thin film solar cells provide improved efficiencies over conventional silicon based technologies, both of which offer energy from renewable sources rather than from fossil fuels. In the consumer electronics arena, recycling at end-of-life has become essential to recover valuable materials and ensure proper disposal of toxic substances. Yet all of these technologies, thought to be advancing the state of the art in sustainable design require the utilization of resources (materials and energy) and create potential environmental impacts (both human and ecological), as do all product fabrication processes. This paper will review a series of case studies on these technologies highlighting the various types of impacts associated with them, in an effort to guide future development of sustainable technologies such that they require less resource input, generate less environmental impact and/or use fewer toxic substances.Speaker(s):
Sustainable development in material sciences includes societal aspects that encompass chemistry, physical sciences, toxicology, medicine, etc., in both academia and the industrial world. Nanomaterials and associated technologies are making their forays into many areas such as energy, transportation, communication, health (drug delivery, imaging and regenerative medicine), environment, and so on. All these applications should be developed keeping their life cycle in mind from production to recycling. A general panel discussion was organized by the French government and scientific institutions on nanotechnologies between 2009 and 2010 (National Commission Public Debate). Even if the idea of having exchanges between academics, politicians, experts and the general population was interesting, it was harder to execute. This is why certain studies in the field of Social Sciences and Humanities (SSH) have helped to understand which factors are involved in communication and how mental representations are built into these kinds of panel discussions with a large spectral band of communicants [1-2]. The dialogue among these disparate elements proved that a lot of headway needs to be made in this area. In that context, these representations depend not only on objective knowledge, but also on subjective perceptions of the benefits/risks ratio relating to the use of nanomaterials and nanotechnologies.
To this end, a specific project based on an interdisciplinary approach was developed in the Lorraine Region including researchers in SSH (psychology, history, and philosophy), materials, chemistry, physics, biology and medicine. Started in 2013, this exploratory project was called PERSONA (PERception of SOcial risks and NAnotechnology).
We will present herein how nanotechnologies, as a still young field, can evoke different perceptions and levels of acceptance. So far our research has been limited to specific school populations (high school and university) with the immediate aim of developing the survey protocol. Naturally, this is the first step to a much broader study to be carried out in conjunction with academic, and industrial players. We will also discuss the risks, threats, levels of acceptance, trustworthiness, perceived benefits, and understanding, all which are influenced by psychological, sociological and cultural factors. The classic risk/benefit model is not sufficient enough to understand and explain the complexity and uncertainty of the impact that nanomaterials have on health, the environment, etc. A new concept of assessing risks (objective as well as perceived), and safety, taking into account the entire life-cycle of nanomaterials. This study aims to contribute towards a more sustainable development and research methods concerning nanomaterials and nanotechnology.
The disposal of materials at the end of their lifecycle, especially for complex manufactured products, presents challenges for protecting the environment and human health. In particular, used automobiles are disposed of by removal of various component parts, followed by shredding, which may emit particles into the atmosphere that may be subsequently deposited onto soil or into water. Further, worldwide automobile production is increasing (68 million cars in 2014 versus 41 million in 2010). In this study, air particulates were collected over several days by DRUM Impactor downwind of an automobile shredding operation located near the ocean, size separated, and analyzed by SEM and TEM, and EDXS, in order to determine their particle size distribution and corresponding chemical composition. Results for larger particles (2.5 to 10.0 μm aerodynamic particle size fraction) showed mainly diatoms and salts, consistent with the location of the plant near the ocean, and aluminosilicates, consistent with dust particles from geological sources. Sulfur, attributed to shipping traffic, was also detected. As aerodynamic particle size decreased from 10 μm to 0.09 μm, particle loading decreased and composition shifted to mainly carbon, oxygen, aluminum, and sulfur. Iron was also found and primarily present in the form of spherical particles that were ~ 1 μm in diameter, as determined by SEM, indicating they originated from a combustion process. Implications of these results for the environment, particularly soil and water deposition, and for human health, as a result of inhalation, are discussed.Speaker(s):
The Materials Project (materialsproject.org) uses supercomputing and informatics to compute and disseminate properties of all known inorganic bulk solid materials. Through web pages and web-powered interfaces, the Materials Project currently makes available over 65,000 compounds and over 43,000 bandstructures as well as an unprecedented number of other data such as elastic tensors. With roughly 15,000 users, it is one of the success stories of the Materials Genome Initiative. To achieve this result, the team has put a great deal of work and thought into the underlying computing and informatics infrastructure. This talk will attempt to describe, in clear and straightforward language without the usual alphabet soup of technology acronyms, the essential aspects of this infrastructure and lessons learned in its implementation. The talk will conclude with a preview of some of the data mining efforts and the "user contributions" framework for integrating experimental and other types of external community data into the core database.Speaker(s):