Combining Fabrication and Chemistry, Grace Han Creates Groundbreaking Sustainable Materials

When it comes to creative solutions to many of the world’s practical challenges, Assistant Professor of Chemistry Grace Han loves running a lab that looks for novel ways to uncover just the right, often unexpected, technology. It’s a skill that was seen in full force at this year’s SPROUT Awards, when teams from Grace’s lab took home two prestigious SPROUT grants. 

The teams are working on two very different technologies, but ones that share at least two things in common: an interdisciplinary approach to chemistry, and a desire to solve ubiquitous challenges in both everyday life and industrial applications.

Grace hails from MIT, where she completed her PhD. She was looking to stay in Boston, both because of the strong research community, and because of her own unique research interests. Though a chemist, Grace’s research combines engineering approaches as well. She needed access to both analytical facilities and fabrication tools, something most easily accessed here in Boston’s academic labs. Friends spoke highly of Brandeis as a good place to start as junior faculty, noting that the environment is very collegial and supportive of rising researchers. Now, Grace heads up her own lab, the Han lab, working on problems at the intersection of chemistry and engineering.

The solutions that won her teams the SPROUT 2019 grants embody that interdisciplinary approach perfectly.

The first is a photo-switchable adhesive, with applications in both industrial and consumer uses. Grace and her team identified novel molecules that respond to light by changing structure. It’s possible to then harvest the energy generated by the changing of the structures. Interested in fundamental switching action of molecules, she’s using TEM to look at atoms and how they move and change structure in response to light, the team has come up with an adhesive that selectively debonds under certain circumstances.

Though their focus is often on fabrication, “we are still chemists,” says Grace. Their focus is on looking at organic molecular structures, and by selecting the right structural group, synthesizing molecules. Their goal is to apply synthetic molecules to specific applications, especially nanodevices and energy.

Adhesives are everywhere. You cannot easily control adhesive strength or predict how an adhesive will deteriorate. In one of the first applications she envisions for the adhesive, microchips, debonding can be especially challenging, particularly under conditions of high pressure or high temperature, in which it can be difficult to access components if they need to be modified. With her solution, users can still access components and remove adhesive when needed.

If this application succeeds, the goal is to use in it many more, including those meant for consumers. That will involve custom-designing each product for each application, taking into account the environment in which they will be working.

The other solution that won an FY 2020 SPROUT grant is one that keeps engine oil warm in freezing conditions. Grace’s team was looking to make oil heating both more sustainable.  In areas where temperatures often drop below -20 °C (-4 °F), such as the northern US and Canada, cars have trouble starting up. At temperatures below 0 °C, the oil is thicker and denser than usual and increases friction wearing down the engine parts. Researchers in Grace Han's lab plan to replace the energy-inefficient block heaters with novel materials that store and release heat in response to changing environment.

Current applications use electricity. A lot of people have to plug in the device 3-4 hours before they drive, getting up early or using automatic scheduling mechanisms that can fail. Many users leave block heaters on overnight to avoid this. This wastes electricity. So why not eliminate electricity? But where to get heat? Molecules can store energy. Grace’s solution utilizes the waste heat coming from the running engine. It stores it in a novel type of material that crystalizes in a controlled manner, and then releases it in the morning.

What’s next for Grace? It’s been almost a year since she started her lab; inherited students from another group. One avenue is to further develop the technologies that won SPROUT grants. One of her postdocs will be participating in the Brandeis I-Corps program over the summer, analyzing customer needs and identifying the target market for these technologies. Grace has seen many friends at MIT participate in I-Corps; when the opportunity presented itself here at Brandeis, Grace made sure someone on her team took advantage of it.

Another future path is to progress with their current research, directly looking at the atoms of molecules--when they switch, how they move. It’s an exciting area chemistry and Transmission Electron Microscopy (TEM). Not too many people have access to the tools needed for this type of research. Researchers need synthetic materials that mimic organic materials, and then need access to high-power TEM. Being part of Brandeis University’s world-class chemistry department gives Grace and her team the access they need to do this groundbreaking research. The team is also looking more into how photo--switching molecules move and how light exposure can change the collective interactions between molecules. This is a unique field of endeavor, one that no one else is working on worldwide.

When asked for one word to summarize her work, Grace says: “control. We want to find a way to control phenomena that are difficult to control with conventional methods. We also want to control light, train light to do the tasks that we want to see. That’s the core value of what I do.” With support from Brandeis Innovation, Grace is well on the way to identifying novel ways to control fundamental phenomena, to better the environment and human life.