Thermoresponsive and Strain-Sensitive Hydrogels with Inscribable Transparency-Based Dynamic Memory Behaviors

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Intelligent hydrogel dressings are crucial for personal health management, requiring optical transparency, stretchability, and conductivity.
• Current limitations include weak perceptive elements and the use of black conductive polymers, hindering advanced hydrogel fabrication.

Purpose of the Study:

• To develop smart hydrogels with inscribable dynamic memorizing-forgetting transparency behavior.
• To create a material capable of perceiving environmental stimuli and storing/recalling information.

Main Methods:

• In situ degradation and immobilization of conductive polydopamine-doped polypyrrole (PDA-PPy) nanodots into a poly(NIPAm-co-acrylic acid) copolymer/polyacrylamide (PNAc/PAM) network.
• Utilizing temperature-induced structural shifts and pH-dependent protonation for transparency control and information encoding.

Main Results:

• The fabricated hydrogels exhibit optical transparency (~64.99%), stretchability (~1052%), self-adhesion (21-105 kPa), and high conductivity (~0.8 S/m).
• Demonstrated temperature-induced reversible transparency control and programmed dynamic memory for information memorizing-forgetting-recalling based on pH-engraved transparency evolution.
• Successfully applied as near-infrared (NIR) light-controlled drug release carriers and soft sensors with high strain sensitivity (GF = 5.98) and rapid response (139 ms).

Conclusions:

• The developed smart hydrogels offer a novel platform for advanced health management applications, including drug delivery and wearable sensors.
• The unique dynamic transparency and memory capabilities pave the way for sophisticated bio-integrated devices.
• The material's properties address key limitations in current intelligent hydrogel development.