An Ultrastrong and Highly Stretchable Polyurethane Elastomer Enabled by a Zipper-Like Ring-Sliding Effect

Area of Science:

• Materials Science
• Polymer Chemistry
• Supramolecular Chemistry

Background:

• Elastomers require a balance between mechanical strength and stretchability.
• Conventional methods often involve a tradeoff, where improving one property compromises the other.
• Sacrificial bonds can enhance stretchability but typically reduce mechanical strength.

Purpose of the Study:

• To overcome the inherent tradeoff between mechanical strength and stretchability in elastomers.
• To introduce a zipper-like sliding-ring mechanism into a hydrogen-bond-crosslinked polyurethane network.
• To enhance the performance of polyurethane networks using supramolecular strategies.

Main Methods:

• A supramolecular strategy was employed using a zipper-like sliding-ring mechanism.
• A hydrogen-bond-crosslinked polyurethane network was utilized.
• A small amount (0.5 mol%) of an external additive, a pseudo[2]rotaxane crosslinker, was introduced.

Main Results:

• A dramatic increase in both mechanical strength and elongation (nearly one order of magnitude) was observed.
• The enhancement is attributed to a unique molecular-level zipper-like ring-sliding motion.
• This motion efficiently dissipates mechanical work within the solvent-free network.

Conclusions:

• A distinct and general strategy for creating high-performance elastomers was developed.
• The study demonstrates the potential of artificial molecular machines in solvent-free polyurethane networks.
• This research offers a pathway for designing advanced materials with superior mechanical properties.