Healing, flexible, high thermal sensitive dual-network ionic conductive hydrogels for 3D linear temperature sensor.

Area of Science:

• Materials Science
• Polymer Chemistry
• Sensor Technology

Background:

• Developing advanced materials for flexible electronics is crucial for wearable devices and soft robotics.
• Hydrogels offer biocompatibility and flexibility, but often lack robust sensing capabilities and durability.
• Integrating nanomaterials like carbon nanotubes can enhance thermal and electrical properties of hydrogel-based sensors.

Purpose of the Study:

• To fabricate a novel temperature sensor utilizing multi-wall carbon nanotubes (MWCNTs) composite polyacrylamide/Fe3+-polyacrylic acid (PAM/Fe3+-PAA) double network (DN) hydrogels.
• To investigate the thermal sensitivity, mechanical flexibility, and self-healing properties of the developed DN hydrogel sensor.
• To explore the potential application of this sensor in soft robotics and for temperature detection on non-planar surfaces.

Main Methods:

• In situ polymerization and maceration were employed to synthesize the MWCNT-based DN hydrogel.
• The fabricated hydrogel was characterized for its thermal sensitivity, stretchability, and self-healing capabilities.
• A linear-shaped sensor design was developed for effective attachment to curvilinear surfaces.

Main Results:

• The DN hydrogel exhibited excellent thermal sensitivity, improved by the MWCNTs' thermal conductivity.
• The temperature sensor demonstrated high stretchability (up to 750% strain) with a sensitivity of 9.4%/°C at 200% strain.
• The hydrogel displayed remarkable self-healing properties for both mechanical and sensing functionalities, along with high stability under bending and torsion.

Conclusions:

• The MWCNT-based DN hydrogel is a promising material for flexible, self-healing temperature sensors.
• The sensor's high sensitivity, stretchability, and self-healing ability make it suitable for advanced applications, including soft robotics.
• The linear design facilitates accurate temperature measurement on complex, non-planar surfaces, enhancing practical utility.