Modern society is now starting to feel the real-world effects of climate change, after more than a century of unrestrained carbon emissions, overuse of natural resources, and irresponsible production of material waste. The rise of atmospheric carbon dioxide has contributed to a warming climate, which means rising sea levels, more droughts, heat waves, and wildfires, and stronger, more frequent tropical storms.
Confronting these challenges will take an all-hands-on-deck approach to adapt to changes that have already taken place and prevent things from getting worse in the future. While governments and businesses can try to affect change through regulation, policy, and investment, science and engineering can play a crucial role by creating new technologies that will change the way we live, the products we use, how we travel, and how we power our world.
Scientists and engineers at the University of Chicago and Argonne National Laboratory are already answering the challenge, using biomaterials, advanced polymers, and artificial intelligence to engineer new materials that are fully recyclable and biodegradable from the ground up, without sacrificing the useful qualities of traditional plastics and consumer products. At the same time, these new materials can be engineered with specific properties to incorporate them into a new generation of electronics, better batteries, clean energy systems, and more.
This work has the potential to advance technology across the board, while reducing environmental harms and enabling human society to move forward in a more sustainable manner. With a decade of advances in molecular engineering, a storied history of materials science in the physical sciences, and crucial expertise and resources from Argonne, UChicago can transform the way in which impactful materials science and engineering is done, driven by sustainability goals and in coordination with insights from economics and policy.
Rethinking plastics from the ground up
Perhaps no material has contributed more to our modern way of life than plastic. Plastic—made from polymers, or large molecules consisting of many repeating subunits—is lightweight, strong, flexible, and most importantly, inexpensive to produce. It keeps our food fresh and makes our clothes warm. It’s in the circuit boards and cases of our smartphones and computers, it makes our cars and aircraft lighter and more fuel-efficient, and it saves lives in things like helmets, airbags, face masks, and medical equipment.
But one advantage of plastic, by design, is also a curse: it can take centuries to break down, if at all. The world produces more than 350 million metric tons of plastics annually—an already staggering number expected to reach 1,800 million tons by 2050—and yet 60% of all plastic ever produced has been thrown away in landfills or the oceans. The problem is so bad that it has been estimated that plastic in our oceans will outweigh all the fish in our seas by 2050.
Many of us think we’re doing our part to save the planet by dutifully separating paper and plastics for the recycling bin. But one of the reasons plastics are so useful and ubiquitous is because they were never designed to break down in the first place, no matter how they are disposed of by consumers. Modern-day plastics are also derived from fossil fuels like petroleum and natural gas.
“When plastics were first designed 50 years ago, they were never meant to be degradable,” said Stuart Rowan, Barry L. MacLean Professor for Molecular Engineering Innovation and Enterprise at the Pritzker School of Molecular Engineering (PME) and the Department of Chemistry, with a joint appointment at Argonne National Laboratory. “The end of life wasn’t planned, because they could always make more.”
Rowan and his colleagues are working on a unique way to overcome both of these challenges by creating plastic-like materials with the ultimate renewable material: plants. Cellulose, the material that makes up the cell walls of plants, is a natural polymer that can be used to make bioplastics. There are already some commercially available plastics made from plants, but they aren’t quite as strong or durable as traditional plastics. Rowan and his lab are working on ways to improve bioplastics to compete with traditional plastics at a competitive cost.
One method is by extracting cellulose nanomaterials from Miscanthus giganteus, a perennial grass with bamboo-like stems that can grow over 12 feet a season. These grasses have drawn a lot of attention from researchers as a potential biofuel because they’re hardy, use water efficiently, and can grow on marginal land and thus don’t compete with food crops.
Working with researchers at Argonne, Rowan and his team have developed processes to extract cellulose nanomaterials from these grasses at an industrial scale. Now, they’re studying them to see how they can be used to improve bioplastics by increasing their resistance to temperature, for example, or improving their barrier properties to create better packaging.
They are also working with other materials researchers at PME and computer scientists from UChicago and Argonne to use artificial intelligence and machine learning to help design the next generation of plastics that are engineered to be more recyclable or biodegradable. AI can be used to identify key characteristics of materials, model the millions of combinations of properties and structures that give them the desired properties, and determine ways to engineer them with new functionality and performance for sustainability.
Democratizing electronics manufacturing
Another significant source of plastic material waste comes from consumer electronics, from smartphones and laptops to TVs, video game consoles, and all of their accessories. Only 17% of the nearly 54 million metric tons of electronic waste generated in 2019 was recycled, much of which was made from plastic and polymer-based materials. To tackle this issue, Rowan and Junhong Chen, Crown Family Professor of Molecular Engineering at PME and lead water strategist at Argonne, are working on another innovative project to transform how electronics are manufactured.
In 2020, Rowan, Chen and colleagues from UChicago, Northwestern, University of Illinois Urbana-Champaign (UIUC) and the University of Illinois at Chicago received a $9.15 million research grant from the National Science Foundation to develop a sustainable manufacturing system for producing biodegradable electronic devices. Over the course of the five-year project, they hope to develop a prototype for an accessible manufacturing system that would eventually allow anyone to 3D print electronic devices at school, libraries, or even at home.
The system will use inks derived from plants, using the same cellulose materials that Rowan is learning how to cultivate and extract from grasses. Right now, most 3D printing is used to create passive, structural components, but Chen says that these bio-based inks can be engineered with different metallic, semiconducting, or insulating properties to be used in electronics. Rowan is working with plant biologists from UIUC to understand how different growing conditions affect the yield and type of cellulose nanomaterials they can harvest from the plants, and how different conditions affect their functional properties.