A 3D representation showing two monomers developing a reversible double-hydrogen bond that decelerates the polymer’s motion without forming an elastic network has been unveiled. Credit goes to S. Nian and team, as reported in Phys. Rev. Lett. 130, 228101 (2023).
Pioneered by the University of Virginia, a research group has carried out an extensive study on associative polymers, substances known for their distinctive self-repairing characteristics. The findings seem to dispute established theories regarding the material’s molecular behavior.
The investigation was headed by Liheng Cai, an assistant professor of materials science, engineering, and chemical engineering at UVA. According to Cai, the newfound understanding of these materials is particularly significant due to their extensive range of applications in our everyday lives, including recyclable plastic production, tissue engineering, and even viscosity adjustment in paint to avoid dripping.
Published in the journal Physical Review Letters, the breakthrough came from innovative associative polymers produced in Cai’s lab at the UVA School of Engineering and Applied Science by his associates, postdoctoral researcher Shifeng Nian and Ph.D. student Myoeum Kim. This major development is the result of a theory Cai co-developed prior to joining UVA in 2018.
Cai highlighted, “Shifeng and Myoeum essentially devised an unprecedented experimental framework to scrutinize associative polymer dynamics in ways previously unachievable.”
Polymer dynamics and behavior, including factors like the temperature at which molecular motion becomes rigid and glass-like, viscosity, and elasticity, were significantly influenced by reversible interactions in these new associative polymers. These traits, often desired in combination, play a crucial role in designing biomaterials compatible with human tissue and capable of self-restoration post-injection.
For the past three decades, it was widely accepted that intact reversible bonds act as crosslinkers, producing a rubbery substance. However, the findings of the UVA-led team contradict this notion.
Working in tandem with Shiwang Cheng, an assistant professor at Michigan State University with expertise in flow dynamics, the team meticulously assessed their polymers’ flow behavior across varying time scales.
Cheng noted, “This involves meticulous control over the local environment, like the polymers’ temperature and humidity. Over the years, my lab has developed a series of methods and systems for this purpose.”
The team’s research revealed that these bonds can slow down polymer motion and dissipate energy without establishing a rubbery network, overturning the long-held belief that reversible interactions primarily impact the polymers’ viscoelastic spectrum rather than their glass-like properties.
The research, “Dynamics of Associative Polymers with High Density of Reversible Bonds,” is featured in the June 2 issue of Physical Review Letters, the American Physical Society’s premier publication. It also leads in Physics, the society’s digital magazine. Notably, it has been chosen as an Editors’ Suggestion, an honor bestowed on only one in six accepted letters.
The National Science Foundation CAREER award backs Cai’s research on associative polymers, with additional funding from UVA, including the LaunchPad for Diabetes Fund. Cai and his team are determined to continue their efforts to further establish the scientific base for these materials’ utilization.
Table of Contents
Frequently Asked Questions (FAQs) about Associative Polymers
What are associative polymers?
Associative polymers are unique materials characterized by their self-healing properties. These polymers consist of molecular subunits, or moieties, which are held together by reversible bonds. These bonds can break and re-form, giving associative polymers macroscopic properties not seen in conventional polymers.
Who led the research on associative polymers?
The research on associative polymers was led by Liheng Cai, an assistant professor of materials science, engineering, and chemical engineering at the University of Virginia. Cai’s team included postdoctoral researcher Shifeng Nian and Ph.D. student Myoeum Kim.
What are the practical applications of associative polymers?
Associative polymers have a multitude of applications in everyday life. They are used in the engineering of recyclable plastics, human tissue engineering, viscosity adjustment in paint to prevent dripping, as viscosity modifiers in fuels, and to create tough self-healing polymers. They can also engineer biomaterials with physical properties critical to tissue engineering and regeneration.
How do associative polymers function at the molecular level?
At the molecular level, associative polymers have moieties, or molecular subunits, that are held together by reversible bonds. These bonds can break and re-form, providing the polymers with unique macroscopic properties. The new research conducted by Liheng Cai’s team found that these bonds can slow down polymer movement and dissipate energy without creating a rubbery network.
What is the significance of the new study on associative polymers?
The new study challenges a long-held understanding of how associative polymers function at the molecular level. It revealed that the reversible bonds in associative polymers can slow down polymer movement and dissipate energy without creating a rubbery network, contradicting the widely accepted belief that intact reversible bonds act as crosslinkers producing a rubbery substance. This new perspective may offer opportunities to improve the understanding of polymer physics and may shift thinking about how to engineer polymers with optimized properties.
More about Associative Polymers
- University of Virginia
- Materials Science and Engineering at UVA
- Physical Review Letters
- National Science Foundation CAREER award
- Michigan State University’s Department of Chemical Engineering and Materials Science
- American Physical Society
7 comments
Very interesting, can’t wait to see what they do next with these polymers. Its stuff like this that keeps me hooked to science.
sometimes i wonder if we’re living in the future already with these kinds of discoveries… so cool!
These are the kind of things they shud be teaching in school, real useful stuff.
Wow this stuff sounds like its from a sci-fi movie, self-healing materials? Insane!
It’s amazing how much we’re advancing in the field of polymers. I mean, self-healing materials, that’s incredible, isn’t it?
Man, this is sooo cool. kudos to the UVA team.
Seriously, how is this even possible? Sounds like magic, but its just science. amazing stuff!