‘Magic’ Solvent Could Improve Polymer Coatings
An all-dry polymerization technique developed by researchers at Cornell University reportedly uses reactive vapors to create thin films with enhanced mechanical strength, kinetics and morphology.
The researchers says that this method can be applied to various methacrylate and vinyl monomers for polymer coatings, including in microelectronics, antifouling for ship hulls or separation membranes for wastewater treatment purification.
The research was recently published in the journal Nature Synthesis. The lead author is doctoral student Pengyu Chen, alongside co-senior authors Rong Yang, assistant professor in the Smith School of Chemical and Biomolecular Engineering in Cornell Engineering; and Jingjie Yeo, assistant professor in the Sibley School of Mechanical and Aerospace Engineering.
About the Process
Chemical vapor deposition (CVD) is a process used to make defect-free inorganic nanolayer materials in semiconductor manufacturing and in the production of computer microchips. However, organic polymers aren’t always able to be used since the process requires materials to be heated to thousands of degrees.
While it’s possible for a lower-temperature counterpart to be used for polymer synthesis, Yang says it is limited because “over the years, people have grown to the boundary of the chemistry you can make with this method.”
“Magic” solvent: A new all-dry polymerization technique developed @CornellEng uses reactive vapors to create thin films with enhanced properties that could lead to improved polymer coatings for advanced batteries and therapeutics. @NatureSynthesis https://t.co/3gRayqqOQ2
— Cornell Chronicle (@CornellNews) February 13, 2023
According to the university, Yang’s lab studies how vapor-deposited polymers interact with bacterial pathogens and how bacteria then colonize polymeric coatings in paint or biomedical devices, for example. The team then wanted to develop a different approach to diversify CVD polymers by using a “magic” solvent, or inert vapor molecule.
The solvent is reportedly not incorporated into the final material, but interacts to produce new material properties at room temperature. Yang describes this “old chemistry but with new features.”
“This scalable technique of initiated chemical vapor deposition polymerization allows us to make new materials, without redesigning or revamping the whole chemistry. We just simply add an ‘active’ solvent,” said Yang.
“It’s a little bit like a Lego. You team up with a new connecting piece. There’s a ton you can build now that you couldn’t do before.”
The solvent, Cornell reports, interacted with a common CVD monomer via hydrogen-bonding.
“It is a novel mechanism, although the concept is simple and elegant,” Chen said. “Building on this interesting strategy, we are developing a robust and generalizable science of solvation engineering.”
The lab then simulated the molecular dynamics behind the solvent and monomer interaction, as well as how their stoichiometry could be tuned.
“We distinguished the effects of different solvents at the molecular scale and we clearly observed which solvent molecules were more inclined to bind with the monomer,” Yeo said. “Thus, we can eventually screen which Lego pieces will be able to fit best with each other.”
Nanoindentation testing was then conducted on the resulting thin film, finding that the solvation mechanism had strengthened the material. The solvent also reportedly caused the polymer coating to grow faster and change its morphology.
“This adds a new dimension to materials design. You can imagine all kinds of solvents that could form hydrogen-bonding with the monomer and manipulate the reaction kinetics differently,” Yang said.
“Or you can have solvent molecules incorporated into your material permanently, if you design the molecular interaction correctly. There’s so much to explore with this added degree of freedom going forward.”
Co-authors also included Shefford Baker, associate professor of materials science and engineering, Zheyuan Zhang and Zach Rouse. The study was conducted at the Cornell Center for Materials Research.
The research was supported by the National Science Foundation, the U.S. Department of the Navy’s Office of Naval Research and the Fleming Scholarship.
