Dynamic hofmeister effect-engineered thermosensitive ionic conductive hydrogel with 3D plasticity and environmental...

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Ionic conductive hydrogels are key for wearable devices, but existing sensors are limited to single-signal detection.
• Developing multimodal sensors is crucial for expanding the capabilities of wearable electronic devices.
• The scientific community seeks advanced hydrogel materials for robust and versatile sensor applications.

Purpose of the Study:

• To develop a novel 3D printable hydrogel capable of multimodal sensing.
• To create a highly durable and environmentally responsive hydrogel material.
• To demonstrate the utility of the hydrogel in advanced wearable sensors for diverse applications.

Main Methods:

• Synthesized a semi-interpenetrating polymer network hydrogel (GSA-PNIPAM@Fe3+/AS) via photocuring gelatin, sodium alginate, and N-isopropylacrylamide.
• Utilized the Hofmeister effect to reduce gelatin hydration, promoting a triple-helix structure and a tightly cross-linked network.
• Characterized the hydrogel's mechanical properties, ionic conductivity, swelling resistance, and temperature responsiveness.

Main Results:

• Achieved a tough, swell-resistant hydrogel with toughness of 661 kJ m⁻³, compressive modulus of 30 MPa, and ionic conductivity of 1.78 S m⁻¹.
• Demonstrated long-term swelling stability, reaching a plateau at 80% equilibrium swelling ratio after 12 days.
• Exhibited excellent responsiveness over a wide temperature range (-10 to 50 °C).
• Developed sensors capable of recording multidimensional human movement, monitoring body temperature, and decoding underwater Morse code.

Conclusions:

• The novel GSA-PNIPAM@Fe3+/AS hydrogel provides a flexible and effective platform for multimodal wearable sensors.
• The developed hydrogel exhibits superior mechanical and environmental properties, suitable for challenging environments.
• This research enhances the potential of flexible electronic devices through advanced hydrogel material development.