Ultrasensitive and Highly Stretchable Multiple-Crosslinked Ionic Hydrogel Sensors with Long-Term Stability.

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Flexible hydrogels are crucial for wearable sensors but suffer from poor adhesion, low sensitivity, and limited self-recovery.
• Existing hydrogel limitations hinder their widespread application in advanced sensing technologies.

Purpose of the Study:

• To develop a multifunctional hydrogel with enhanced properties for wearable sensor applications.
• To address limitations of current hydrogels, including adhesion, sensitivity, and durability.

Main Methods:

• A one-pot synthesis method was used to create a multiple-crosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide) (P(SBMA-co-AAm)) hydrogel.
• Incorporation of ions, glycerol, and zwitterionic monomer (2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide) to improve properties.

Main Results:

• The P(SBMA-co-AAm) hydrogel demonstrated excellent stretchability (2900% strain), self-healing capabilities, and transparency.
• Achieved a high gauge factor of 43.4 and strong adhesion of 20.9 kPa due to improved ion transportability and dipole-dipole interactions.
• Reduced freezing point and improved moisture retention were observed.

Conclusions:

• The developed multifunctional hydrogel overcomes key limitations of existing materials for wearable sensors.
• The hydrogel shows significant promise for next-generation biomedical applications, including soft robots and health monitoring devices.