Aromatic foldamers as molecular springs in network polymers

Area of Science:

• Polymer Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Traditional polymer networks often lack efficient energy dissipation mechanisms.
• Foldamers offer unique structural and dynamic properties for advanced material design.

Purpose of the Study:

• To develop novel polymer networks utilizing ortho-phenylene (oP) foldamers as crosslinkers.
• To investigate the impact of oP crosslinkers on the mechanical properties, particularly energy dissipation and elasticity, of polymer networks.

Main Methods:

• Synthesis of polymer networks crosslinked with oP foldamers.
• Nuclear Magnetic Resonance (NMR) spectroscopy to confirm foldamer structure and folding.
• Mechanical testing to evaluate energy dissipation and elasticity compared to control networks.

Main Results:

• NMR confirmed that the oP crosslinkers were well-folded within the polymer network.
• oP-crosslinked networks demonstrated significantly enhanced energy dissipation and elasticity compared to divinylbenzene crosslinked networks.
• Energy dissipation correlated with the number of helical turns in the oP foldamer, increasing with higher turn counts.

Conclusions:

• oP foldamers serve as effective crosslinkers, imparting superior energy dissipation and elastic properties to polymer networks.
• The reversible unfolding of oP units under strain is the primary mechanism for enhanced energy dissipation.
• Foldamer design, specifically the number of helical turns, can be tuned to optimize energy dissipation in polymer materials.