Bioinspired Sarcomeric Double-Network Hydrogels for Programmable Mechanics with Ultralow Hysteresis

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Hysteresis in hydrogels, caused by intermolecular friction, typically leads to fatigue under complex loading.
• Developing hydrogels with controlled mechanical properties is crucial for advanced engineering applications.

Purpose of the Study:

• To fabricate a sarcomere-inspired double-network hydrogel with effectively regulated hysteresis.
• To investigate the mechanisms behind hysteresis reduction and the material's response to cyclic loading.
• To evaluate the hydrogel's performance in extreme conditions and potential applications.

Main Methods:

• Fabrication of a double-network hydrogel using polyacrylamide, alginate, and phytic acid.
• Application of pre-tensile processes to regulate hysteresis.
• Characterization of hysteresis under various preloading conditions, including cyclic tensile loading.
• Assessment of material performance at low temperatures and after prolonged cycling.

Main Results:

• The developed hydrogel exhibits ultralow hysteresis (≤0.02%) after specific pre-tensile treatment, with potential for negative hysteresis.
• The material demonstrates smart responses to cyclic loading, mimicking sarcomere behavior.
• The hydrogel maintains reliable performance at temperatures as low as -20 °C.
• Electrical sensing applications showed stable signals (ΔR/R₀) after 1000 cycles, indicating superior reliability.

Conclusions:

• A novel hydrogel design strategy allows for programmable hysteresis control.
• The biomimetic hydrogel's ultralow hysteresis and reliability make it suitable for demanding engineering fields, particularly electrical sensing.
• This work offers an innovative approach for developing high-performance smart hydrogels.