Conductive and Self-Adhesive Polyelectrolyte Hydrogel Sensor for Flexible Wearable Devices and Reusable Physiological...

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Hydrogel-based flexible wearable devices and physiological electrodes are gaining traction due to their biocompatibility and comfort.
• Limitations in current hydrogel technology include insufficient sensitivity for minute deformations and low electrical conductivity.
• Addressing these limitations is crucial for advancing wearable sensor and electrode performance.

Purpose of the Study:

• To develop a multifunctional conductive polyelectrolyte hydrogel with improved adhesion and environmental tolerance.
• To enhance the sensitivity, conductivity, and long-term stability of hydrogel-based sensors and electrodes.
• To demonstrate the utility of the developed hydrogel in flexible wearable devices and reusable self-adhesive electrodes for physiological signal monitoring.

Main Methods:

• Synthesized a conductive polyelectrolyte hydrogel using 3-(methacryloylamino)propyl-trimethylammonium chloride.
• Incorporated tannic acid and glycerol into the hydrogel network to improve adhesion and environmental tolerance.
• Fabricated flexible wearable devices and reusable self-adhesive electrodes for physiological signal acquisition.

Main Results:

• The polyelectrolyte hydrogel exhibited low hysteresis (<10%), high self-adhesion (~50 kPa), excellent biocompatibility, and antibacterial properties.
• Achieved satisfactory conductivity (8.5 mS m⁻¹), remarkable long-term stability (~10,000 cycles), and a wide strain sensing range (0.1%-100%).
• Demonstrated accurate human pulse monitoring and superior signal-to-noise ratio, stability, and sensitivity for electroencephalogram (EEG), electrocardiogram (ECG), and electromyogram (EMG) compared to commercial electrodes.

Conclusions:

• The developed conductive polyelectrolyte hydrogel presents a promising material platform for advanced flexible wearable electronics.
• The material enables stable and accurate long-term signal monitoring for various physiological applications.
• This work paves the way for next-generation wearable devices with enhanced performance and user comfort.