Swelling-Tunable Hydrogels for Self-Transformable Underwater Flexible Electronics with Wireless Communication

Area of Science:

• Materials Science
• Polymer Chemistry
• Flexible Electronics

Background:

• Hydrogels are promising for flexible electronics due to biocompatibility and flexibility.
• Traditional hydrogels face mechanical degradation from swelling, limiting applications.

Purpose of the Study:

• To develop novel HEMA-HEA hydrogels with tunable antiswelling properties and improved mechanical performance.
• To explore their potential in flexible strain sensors and underwater electronic applications.

Main Methods:

• Synthesized HEMA-HEA hydrogels by varying the ratio of hydroxyethyl methacrylate (HEMA) to hydroxyethyl acrylate (HEA).
• Characterized hydrogel properties including swelling ratio, mechanical strength, optical transparency, and self-bonding capabilities.
• Fabricated and tested flexible strain sensors for performance and underwater operation.

Main Results:

• Increasing HEMA content enhanced mechanical properties and reduced swelling ratios, with HEMA5-HEA0 showing a 0.9% swelling ratio.
• HEMA4-HEA1 hydrogels exhibited balanced properties and minimal hysteresis, ideal for strain sensors.
• Fabricated sensors demonstrated high sensitivity, fatigue resistance, and stable underwater operation, enabling motion sensing and wireless communication.
• Postprogrammable shape transformation and autonomous underwater fixation of RFID chips were achieved.

Conclusions:

• HEMA-HEA hydrogels offer tunable antiswelling and robust mechanical properties for advanced applications.
• These hydrogels are suitable for developing high-performance flexible electronics, particularly for underwater environments.
• The study highlights the potential of these materials for complex shape programming and reliable underwater wireless communication.