Ultrastretchable and Self-Healing Double-Network Hydrogel for 3D Printing and Strain Sensor

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Hydrogels are versatile materials with diverse applications.
• Developing advanced hydrogels with enhanced mechanical properties and functionalities is crucial.
• Carrageenan and polyacrylamide are common polymers with distinct cross-linking behaviors.

Purpose of the Study:

• To fabricate a double-network (DN) hydrogel by combining κ-carrageenan and polyacrylamide (PAAm).
• To investigate the self-healing, 3D printing, and strain-sensing properties of the developed DN hydrogel.
• To explore potential applications of the κ-carrageenan/PAAm DN hydrogel in robotics and human motion detection.

Main Methods:

• Fabrication of a DN hydrogel using an ionically cross-linked κ-carrageenan network and a covalently cross-linked PAAm network.
• Characterization of the hydrogel's thermoreversible sol-gel transition behavior.
• Evaluation of mechanical properties, including recoverability, self-healing capability, and strain sensitivity.
• Assessment of the pregel solution's suitability as a 3D printing ink.

Main Results:

• The κ-carrageenan/PAAm DN hydrogel exhibited excellent recoverability and significant self-healing properties.
• The warm pregel solution served as a printable ink for creating complex 3D structures with high mechanical strength after UV exposure.
• The hydrogel demonstrated remarkable strain sensitivity, with a gauge factor of 0.63 at 1000% strain.

Conclusions:

• The developed κ-carrageenan/PAAm DN hydrogel offers a promising combination of self-healing, 3D printability, and strain sensitivity.
• This novel hydrogel material holds potential for advanced applications in soft robotics, wearable sensors, and human motion detection.
• The study highlights the synergistic benefits of combining ionic and covalent cross-linking strategies in hydrogel design.