This excerpt from the Stanford Emerging Technology Review (SETR) focuses on materials science, one of ten key technologies studied in this educational initiative. SETR, a project of the Hoover Institution and the Stanford School of Engineering, harnesses the expertise of Stanford University’s leading science and engineering faculty to create an easy reference tool for policy makers. Download the full report here and subscribe here for news and updates.
Materials science is a foundational technology that underlies advances in many other fields, including robotics, space, energy, and synthetic biology.
Materials are everywhere, from macro features visible to the naked eye to microscopic features far smaller than the diameter of a single human hair. They shape the objects of everyday life and give rise to new possibilities. Materials science cuts across technological areas, contributing to the development of stronger and lighter materials for aircraft, more efficient and lighter solar cells, better semiconductors, biocompatible materials for medical implants, more stable electrodes for batteries, and easily manufactured and recyclable plastics. And, as the electrification of transportation and industry continues, materials design and processing is integral to decarbonization efforts.
The goal of materials science is to understand how the structure of a material influences its properties, and how processing the material can change its structure and therefore its performance. This knowledge can then be used to design new materials with desirable properties for specific uses. The ultimate aspiration, which remains a long way off, is to be able to create materials on demand by specification—put in a request for a material with properties X, Y, and Z, and a 3D printer produces it for you.
Broadly speaking, materials science and engineering research focuses on four major areas. The first is characterizing the properties of materials. The second is modeling materials, which involves predicting material properties based on atomic principles. The third is synthesizing materials with precise control to verify whether their properties are as predicted. The fourth is manufacturing and processing materials with well-characterized properties in sufficient quantities for practical applications.
Worldwide implications
For an example of how materials science could have an impact on a large scale, consider cement and concrete. They are critical building materials; world production of concrete is some 30 billion tons per year. For comparison, the weight of all the concrete in New York City is around 750 million tons, according to the US Geological Survey.
Production of cement, the key ingredient in concrete, is an extremely carbon-intensive activity, contributing to about 8 percent of global CO2 emissions. Limestone is burned to produce lime, thereby releasing CO2. A number of approaches have the potential to reduce the CO2 footprint of cement production. One focuses on using different material inputs in the production process that release less CO2. These inputs are the basis for “supplementary cementitious materials,” which are formulated differently from traditional Portland cement but nevertheless can substitute for it in many cases. Another approach incorporates captured CO2 into concrete during the curing process.
These techniques are all well-proven, but further research is needed to make them economically competitive with traditional CO2-intensive methods of cement production.
Another interesting topic is whether AI machine learning and modeling will be useful in predicting properties of new materials based on what is known about existing materials. Success has been seen with less-complicated materials, but much is to be done and more data needed for complex materials.
Among the challenges of innovating in materials science, and then putting those innovations to use, is that the materials science research infrastructure does not adequately support the transition from research to real-world applications at scale. Such transitions generally require constructing a small pilot project to show whether large-scale manufacturing might be feasible. At that point, the technology is too mature to qualify for most research funding—because the basic science questions do not address issues related to scaling up— but not mature enough to be commercialized. Neither government nor venture-capital investors are particularly enthusiastic about funding pilot projects, so different forms of funding are required to bridge this gap between bench-scale research and company-level investment. There could even be national rapid prototyping centers, where academic researchers find the help and tools to build prototypes and pilot plants for their technology.
Risks and hurdles
As with other areas of technology, concerns arise about the appropriate balance between protecting public safety from possible downside risks and the imperative to move quickly and leapfrog possible competitors. Nanotechnology, for instance, is a large and growing subfield of materials science that has attracted enormous interest in the past twenty years. The FDA created a Nanotechnology Regulatory Science Research Plan in 2013.Today, FDA regulation and review of nanotechnology is governed by Executive Order 13563. Nanoparticles raise particular concerns because their small size may enable them to pass various biological borders such as cell membranes or the blood-brain barrier, and this could harm biological systems. Nanoscale particles inhaled into the lungs, for example, may lodge themselves permanently, causing severe health outcomes including pulmonary inflammation, lung cancer, and penetration into the brain and skin.
Furthermore, because engineered nanoparticles are, by definition, new to the natural environment, they pose unknown dangers to humans and the environment. There are concerns about incorporating nanomaterials into products that enter that environment at the end of their life cycles. As nanomaterials are employed in and considered for electronic and energy products, it is paramount that those materials safely degrade or can be recycled at the end of a product’s life. Policy will be particularly important in shaping responsible end-of-life solutions for products incorporating nanomaterials.
Historically, the United States has led the world in nanotechnology, but the gap between the United States and China has narrowed. Notably, in 2016, the president of the Chinese Academy of Sciences openly announced Beijing’s ambition to compete in this field. As great-power competition intensifies, many researchers are concerned that policy ambiguity could inadvertently hinder innovation by creating obstacles for non-US researchers wishing to contribute to work in the United States and by deterring international collaborations, allies, and partners who are important for advancing the field. There is an urgent need to clarify these policies, particularly delineating fundamental research and export-controlled research.
