Strain-stiffening gels based on latent crosslinking

Area of Science:

• Soft matter physics and polymer science.
• Materials science and engineering.

Background:

• Gels are crucial soft materials with diverse applications but often suffer from mechanical weakness, especially under repeated strain.
• Existing gels lack robust mechanical integrity, limiting their use in demanding applications.

Purpose of the Study:

• To engineer a novel class of responsive gels exhibiting strain-stiffening behavior.
• To design gels with latent crosslinking moieties activated by mechanical stimuli.

Main Methods:

• Incorporation of labile disulfide crosslinks in a protected state within the polymer network.
• Utilizing molecular shielding design elements to control crosslinking activation and strain-sensitivity.
• Subjecting the gels to mechanical compression to induce inter-chain crosslinking.

Main Results:

• The developed gels demonstrate significant strain-stiffening, strengthening upon mechanical compression.
• Latent disulfide crosslinks are activated on-demand by mechanical stress, leading to enhanced mechanical properties.
• Molecular shielding effectively regulates the responsiveness and prevents premature crosslinking.

Conclusions:

• A new class of advanced, strain-responsive gels with on-demand stiffening capabilities has been rationally designed.
• These materials offer tunable mechanical properties and overcome the limitations of conventional weak gels.
• Potential applications include high-performance elastomers, adhesives, foams, films, and fibers.