Linearly Responsive, Reliable, and Stretchable Strain Sensors Based on Polyaniline Composite Hydrogels

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Conductive hydrogels are promising for flexible strain sensors.
• Practical applications are hindered by water evaporation, signal hysteresis, and instability.
• These issues compromise sensor linearity, durability, and reliability.

Purpose of the Study:

• To develop a robust multiple-network conductive hydrogel.
• To overcome the limitations of existing hydrogels for strain sensing.
• To create a material solution for high-performance, reliable flexible strain sensors.

Main Methods:

• Synthesized a novel hydrogel using poly(vinyl alcohol) (PVA), polyacrylic acid (PAA), polyaniline (PANi), and an ionic liquid ([EMIM][TFSI]).
• Characterized the hydrogel's electrical, mechanical, and stability properties.
• Evaluated its performance as a flexible strain sensor.

Main Results:

• The hydrogel exhibited excellent linear piezoresistive response up to 290% strain.
• Achieved high conductivity (0.68 S/cm), fast response/recovery (0.34 s/0.35 s), and a gauge factor of 2.78.
• Demonstrated mechanical robustness (3.7 MPa tensile strength), exceptional cyclic durability (>12,000 cycles), and improved dehydration resistance.

Conclusions:

• The developed multiple-network hydrogel offers a holistic solution for advanced strain sensing.
• This material addresses key limitations, enhancing linearity, durability, and reliability.
• The findings support the use of this hydrogel in wearable electronics and soft robotics.