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Double helical conformation and extreme rigidity in a rodlike polyelectrolyte
Ying Wang1, Yadong He2, Zhou Yu2
1Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA.
Nature Communications
|February 20, 2019
Summary
Researchers discovered a synthetic polymer, poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT), that forms an exceptionally rigid double helix. This discovery offers new possibilities for creating advanced molecular composites with unique properties.
Area of Science:
- Polymer Chemistry
- Materials Science
- Biomimicry
Background:
- DNA's double helix provides significant axial rigidity (~50 nm persistence length).
- Synthetic non-chiral macromolecules rarely adopt double helical structures.
- Understanding synthetic rigid structures is key for advanced materials.
Purpose of the Study:
- To report the discovery of a double helical conformation in a synthetic macromolecule.
- To characterize the rigidity and properties of this novel double helix.
- To explore its potential applications in molecular composites.
Main Methods:
- X-ray diffraction analysis
- NMR spectroscopy
- Molecular dynamics (MD) simulations
Main Results:
- Confirmed a double helical conformation in poly(2,2 '-disulfonyl-4,4 '-benzidine terephthalamide) (PBDT).
- Determined an exceptionally high axial persistence length (~1 micrometer) for PBDT, surpassing DNA.
- Observed high charge density and liquid-like ion motions within the rigid structure.
Conclusions:
- PBDT represents one of the most rigid simple molecular structures known.
- The combination of extreme rigidity and high charge density is crucial for self-assembly of high-modulus molecular ionic composites.
- This finding provides a foundation for developing novel 1D-reinforced composites.
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