Highly Sensitive Zwitterionic Hydrogel for Dual-Mode Temperature Sensing with Zinc Ion Regulation

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Thermoresponsive hydrogels are crucial for portable sensing applications due to their adjustable response range and high sensitivity.
• Developing power-free temperature sensing materials with adjustable ranges and high sensitivity remains a significant challenge for wearable electronics.

Purpose of the Study:

• To develop a zwitterionic hydrogel exhibiting dual optical-electronic thermoresponsive behavior for precise temperature sensing.
• To achieve tunable optical transition temperatures over a broad range using a facile one-pot synthesis.
• To enable dual-mode temperature sensing with high sensitivity and self-healing properties for wearable applications.

Main Methods:

• A one-pot copolymerization strategy was employed using SBMA and AA in the presence of Zn2+ and PLL as a cross-linker.
• The SBMA/AA mass ratio and Zn2+ concentration were regulated to tune the optical transition temperature.
• The hydrogel's ionic conductivity, temperature coefficient of resistance (TCR), and self-healing properties were characterized.

Main Results:

• The zwitterionic hydrogel demonstrated precisely tunable optical transition temperatures from 6.6 to 52 °C.
• The hydrogel exhibited excellent ionic conductivity and an ultrahigh TCR of -7.78%·°C-1 within the physiological temperature range.
• A synchronized visual transparency transition enabled dual-mode optical-electronic temperature sensing, alongside self-healing and robust adhesion.

Conclusions:

• This work presents a versatile design for zinc ion-regulated, dual-mode temperature sensing hydrogels.
• The developed hydrogel shows significant potential for flexible temperature monitoring and visual wearable healthcare electronics.
• The facile synthesis and tunable properties offer a promising platform for advanced sensing technologies.