Dynamic Supramolecular Polyurethane Elastomers Enabling Bioinspired Strain-Adaptive Stiffening to Resolve the...

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Soft robotics and flexible electronics require advanced elastomers with both high strength and softness.
• Natural skin serves as a benchmark for mechanical properties like low modulus and high toughness.

Purpose of the Study:

• To engineer novel dynamically crosslinked supramolecular polyurethanes.
• To achieve skin-comparable mechanical properties, including low modulus, high strength, and room-temperature self-healing.

Main Methods:

• Segmental molecular engineering strategy was employed.
• Incorporation of isophorone diisocyanate (IPDI) chain extender with ureidopyimidinone (UPy) to reinforce hydrogen bonding.
• Utilized entropy-driven elasticity and enthalpy-governed strain-stiffening.

Main Results:

• Developed supramolecular polyurethanes with ultralow initial modulus (<3 MPa).
• Achieved pronounced strain-stiffening, exceptional tensile strength (>50 MPa), and high fracture toughness (∼2×10^5 J m^-2).
• Demonstrated room-temperature self-healing and hydrophobicity for underwater applications.

Conclusions:

• Segment-level molecular engineering enables the creation of dynamic polyurethanes with thermoplastic processability.
• The novel elastomers exhibit skin-like softness and superior mechanical robustness.
• These materials hold significant promise for advanced applications in soft robotics and flexible electronics.