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Published on: January 19, 2016
Mechanostereochemical modulation of polymer mechanical properties
Yi Ding1,2, Wei You2, Guoquan Liu2
1Renji Branch of National Center for Translational Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.
Summary
This study introduces mechanostereochemistry, where dynamic isomers controlled by force dictate polymer properties. This transient-stereostructure-efficacy mechanism offers new pathways for designing advanced materials.
Area of Science:
- Polymer Chemistry
- Materials Science
- Mechanochemistry
Background:
- Stereochemistry, including tacticity and cis/trans isomerism, traditionally dictates polymer properties through fixed structures.
- Existing polymer stereochemistry relies on static factors, limiting dynamic control over material characteristics.
Purpose of the Study:
- To introduce and demonstrate mechanostereochemistry, a paradigm where dynamic isomers influence polymer properties.
- To explore the transient-stereostructure-efficacy mechanism in mechanically interlocked networks.
- To engineer polymers with force-responsive stereochemical configurations.
Main Methods:
- Design and synthesis of two mechanically interlocked networks ([c2]daisy chains).
- Utilizing force-triggered intramolecular motion to generate distinct mechanostereoisomers.
- Characterizing material properties using large-strain shear and tensile tests.
Main Results:
- Mechanically interlocked networks formed distinct mechanostereoisomers: a contracted fisherman's knot (MIN-1) and an extended loop (MIN-2).
- MIN-2, with a loop structure, exhibited lower modulus and less strain hardening than MIN-1 due to reduced network elasticity.
- Material properties demonstrated strain-dependent behavior, diverging significantly at large strains.
Conclusions:
- Mechanostereochemistry enables dynamic control over polymer properties through force-induced isomerism.
- The transient-stereostructure-efficacy mechanism provides a novel approach for material design.
- This research expands the understanding of polymer stereochemistry and its application in high-performance materials.
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