Natural Phytic Acid-Assisted Polyaniline/Poly(vinyl alcohol) Hydrogel Showing Self-Reinforcing Features

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials

Background:

• Polyaniline (PANi) hydrogels offer combined hydrogel and conductive properties for wearable devices and healthcare.
• Mechanical degradation of existing PANi hydrogels under stress limits their long-term application.
• Biological structures inspire strategies for developing durable materials.

Purpose of the Study:

• To develop a self-reinforcing polyaniline/poly(vinyl alcohol) (PVA) hydrogel with enhanced mechanical durability.
• To investigate the role of phytic acid (PA) in promoting in situ polymerization and inducing self-reinforcing features.
• To evaluate the hydrogel's potential as a reliable strain sensor.

Main Methods:

• In situ polymerization of aniline assisted by phytic acid in a PVA hydrogel matrix.
• Characterization of hydrogel structure, mechanical properties (fracture strength, Young's modulus, toughness), and self-reinforcing behavior.
• Assessment of anisotropic structure formation and disassembly via repetitive stretching and swelling.

Main Results:

• The phytic acid-assisted PVA/PANi hydrogel demonstrated significant improvements in fracture strength (20.35 MPa), Young's modulus (22.66 MPa), and toughness (36.24 MJ·m⁻³).
• Repetitive stretching induced self-reinforcing anisotropic structures stabilized by hydrogen bonds between PA/PANi particles and PVA chains.
• The hydrogel maintained its self-reinforcing capabilities even after swelling in water, indicating reusability.

Conclusions:

• Phytic acid plays a dual role in promoting conductive PANi formation and facilitating self-reinforcement in PVA hydrogels.
• The developed hydrogel exhibits persistent mechanical durability and reusability, making it suitable for strain sensing applications.
• This work presents a novel structural growing-reviving approach for creating robust conductive hydrogels.