Block copolymers (BCPs) have been of great interest to researchers in recent years. These nanostructured materials, made from blocks of chemically dissimilar polymers, self-assemble to form microdomains of various morphologies and sizes. They could potentially be used for everything from cleaner water to the next generation of computing.
Researchers, however, have been limited by the inability to regulate the nanostructural and material properties of these materials. For instance, there’s interest in developing BCPs with very small nanodomain sizes to make them more versatile. But various approaches to doing so can interfere with other valuable properties, such as thermomechanical behaviors and processability. As a result, achieving useful materials with domain sizes below 10 nanometers is extremely difficult.
To get around this problem, Mingjiang Zhong is studying a subset of these materials known as Janus graft block copolymers (GBCPs) in collaboration with the teams of Jeremiah Johnson at MIT and Yale’s Chinedum Osuji, associate professor of chemical & environmental engineering. When designed a certain way, GBCPs can be used to make nanostructured polymers with ultra-small nanodomains with diverse morphologies and bulk properties. Zhong, assistant professor of chemical & environmental engineering, published his findings in the journal Angewandte Chemie as a Very Important Paper (VIP)
With a larger backbone and several smaller branches, the structures resemble bottlebrushes. The GBCPs can be tuned by adjusting the length of the material’s backbone or selecting different sidechains. By doing so, the researchers can achieve different thermomechanical properties without sacrificing their command of critical properties. And critically, Zhong was able to achieve a domain size of less than three nanometers.
“That could have huge potential in microelectronics,” Zhong said, adding that it could mean the development of higher-density chips. The field of environmental engineering could also benefit, since smaller domain sizes could allow for the development of more selective membranes for water filters. Zhong is currently collaborating with other Yale researchers on developing applications in both of those fields.
Other co-authors of the study include Zi-Hao Guo, An N. Le, Xunda Feng, Youngwoo Choo, Bingqian Liu, Danyu Wang, Zhengyi Wan, Yuwei Gu, Julia Zhao, Vince Li, Chinedum O. Osuji, and Jeremiah A. Johnson.
Reference: “Janus Graft Block Copolymers: Design of a Polymer Architecture for Independently Tuned Nanostructures and Polymer Properties” by Zi-Hao Guo, An N. Le, Xunda Feng, Youngwoo Choo, Bingqian Liu, Danyu Wang, Zhengyi Wan, Yuwei Gu, Julia Zhao, Vince Li, Chinedum O. Osuji and Jeremiah A. Johnson, 26 April 2018, Angewandte Chemie.