Bond Density Not Energy Controls Polymer Stickiness
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• Physics 16, s80
Experiments present that the sticky conduct of so-called associative polymers is managed by the density of bonding buildings, contradicting theoretical predictions.
L. Cai, S. Nian, M. Kim/College of Virginia
No-drip paint and self-healing supplies are made with polymers that comprise “stickers”—chemical buildings that type easy-to-break bonds. The at present favored concept for the conduct of such polymers assumes that it’s managed by the sticker bond energy. Nevertheless, new experiments by Li-Heng Cai from the College of Virginia and his colleagues name that concept into query [1]. As an alternative, the group’s outcomes point out that sticker density is the important thing management knob for this technique.
The way in which to make sticky polymers—also referred to as associative polymers—is to insert chemical hyperlinks into the molecular chains that make up the polymer. These chemical stickers can type non permanent attachments between chains, slowing the general movement of the polymer. This friction-like impact has proved helpful in controlling the viscosity of paints and fuels. Sticky polymers may reform damaged bonds—a self-healing characteristic that might profit biomaterials used for tissue regeneration.
Of their experiments, Cai and his colleagues synthesized polymers with as much as eight stickers per polymer phase, in distinction with the everyday one. The upper sticker densities resulted in polymers with extra uniform stickiness. In x-ray imaging, the researchers discovered that the stickers interacted with out collapsing into clusters—contradicting theoretical expectations. To elucidate this conduct, they devised a concept that thought of polymer sticker density somewhat than the beforehand used bond energy. Cai says that their observations and modeling may information additional improvement of associative polymers.
–Michael Schirber
Michael Schirber is a Corresponding Editor for Physics Journal primarily based in Lyon, France.
References
- S. Nian et al., “Dynamics of associative polymers with excessive density of reversible bonds,” Phys. Rev. Lett. 130, 228101 (2023).
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