Hydrogel Stack-Tailored Logics and High-Fidelity Multimodal Sensors Promoted by Precisely Evaluated Ionic Migration.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Self-powered flexible sensors are crucial for tactile sensing and wearable electronics.
• Biological ion transport mechanisms inspire the design of tactile perception systems.

Purpose of the Study:

• To develop self-powered multifunctional sensors inspired by biological ion transport.
• To investigate the use of ionomers, MXenes, and carbon nanotubes (CNTs) for enhanced sensor performance.

Main Methods:

• Fabrication of four types of self-powered sensors using cationic poly(diallyldimethylammonium chloride) and anionic sodium polystyrene sulfonate ionomers.
• Incorporation of 2D MXenes and 1D CNTs to optimize electrical conductivity.
• Assembly of sensing units into arrays to achieve precise stimulus discrimination.

Main Results:

• The sensors exhibit a p-n junction configuration with a depletion layer at the ionomer interface.
• Optimized conductivity yielded an open-circuit voltage of ~75 mV and a short-circuit current density of ~67 µA cm⁻².
• Demonstrated distinct rectification behavior (ratio ≈ 8.8) enabling logic circuit functionality and precise discrimination of compression, bending, and directional stress.

Conclusions:

• The developed sensors offer a novel approach for high-performance, self-powered ionic sensing.
• This work presents a new paradigm for designing sensors for next-generation flexible and wearable electronics.
• Each sensing unit exhibits unique characteristics, allowing for advanced tactile discrimination.