A Bilayer Skin-Inspired Hydrogel with Strong Bonding Interface

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Conductive hydrogels offer excellent properties for sports monitoring, healthcare, and energy storage.
• Synthesizing hydrogels with synergistic mechanical and electrical properties remains a challenge.
• Current methods often focus on single-component hydrogels, neglecting multi-component strategies.

Purpose of the Study:

• To develop a bilayer conductive hydrogel with improved mechanical and electrical performance.
• To create a robust interface between hydrogel layers using spray-coated PEDOT:PSS.
• To investigate the material's potential for stretchable electronics and wearables.

Main Methods:

• Fabrication of a bilayer hydrogel structure with a spray-coated PEDOT:PSS interface.
• Characterization of mechanical properties including stretchability, toughness, tensile strength, and elastic modulus.
• Evaluation of electrical properties, conductivity, and performance as a strain sensor.

Main Results:

• The bilayer hydrogel exhibited outstanding stretchability (1763.85 ± 161.66%) and high toughness (9.27 ± 0.49 MJ/m3).
• The material demonstrated good tensile strength (0.92 ± 0.08 MPa) and a decent elastic modulus (69.16 ± 8.02 kPa).
• The strain sensor showed high sensitivity (GF=18.14) and stable performance over 12,500 cycles.

Conclusions:

• The bilayer conductive hydrogel offers superior mechanical and electrical properties compared to single-layer counterparts.
• The PEDOT:PSS interface and modulus matching are key to the material's enhanced robustness and performance.
• This hydrogel is a promising candidate for stretchable electronics, soft robots, and next-generation wearables.