Binary Co-Gelator Strategy: Toward Highly Deformable Ionic Conductors for Wearable Ionoskins

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Increasing demand for wearable electrochemical devices necessitates development of stretchable ionic conductors.
• Conventional ionic conductors often lack sufficient mechanical deformability for seamless integration into wearable platforms.
• Poly(methyl methacrylate) (PMMA) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMI][TFSI]) mixtures yield stiff ionic conductors.

Purpose of the Study:

• To develop a strategy for enhancing the mechanical deformability of ionic conductors.
• To create a highly stretchable and durable ionic conductor suitable for strain sensing applications.
• To investigate the effect of incorporating a flexible polymer on ionic conductor properties.

Main Methods:

• A ternary ionic conductor was synthesized by mixing PMMA (polymer gelator), [BMI][TFSI] (ionic liquid), and poly(butyl acrylate) (PBA) (flexible polymer).
• Mechanical properties (stretchability, elasticity, durability) and electrochemical characteristics were evaluated.
• The influence of PBA content on material homogeneity and performance was assessed, identifying the macrophase separation limit.

Main Results:

• An extremely stretchable (∼1500%) homogeneous ternary ionic conductor was achieved with PBA doping.
• The material exhibited excellent mechanical elasticity (1.8 × 10⁵ Pa) and durability (∼86.3% recovery after 1000 cycles).
• Electrochemical characteristics remained largely unchanged below the 3 wt% PBA macrophase separation limit.

Conclusions:

• The developed ternary ionic conductor offers superior stretchability and mechanical robustness compared to conventional materials.
• Its properties make it highly suitable for advanced strain sensory platforms in wearable electronics.
• The material's large-area motion monitoring capability, even from small pieces, highlights its potential for diverse applications.