Self-Healing E-tongue.

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Polymer Science

Background:

• Self-healing materials are crucial for next-generation wearables and IoT devices, enabling conformal coverage on complex surfaces.
• The layer-by-layer (LbL) technique offers precise thickness control for fabricating thin films with materials like poly(ethylenimine) (PEI) and poly(acrylic acid) (PAA).
• Achieving thin film composites with both controlled conductivity and self-healing properties under ambient conditions remains a significant challenge.

Purpose of the Study:

• To develop novel conductive self-healing thin film composites.
• To investigate the integration of conductive fillers within LbL architectures for enhanced material properties.
• To demonstrate the application of these composites in a self-healing electronic tongue (e-tongue) sensor.

Main Methods:

• Fabrication of distinct LbL film architectures by mixing PEI and PAA with conductive fillers (gold nanorods, PEDOT:PSS, reduced graphene oxides, multiwalled carbon nanotubes).
• Characterization of composite structures and properties using electrical (AC/DC), optical (Raman spectroscopy), and mechanical (nanoindentation) measurements.
• Integration and testing of selected LbL composites as sensing units in a self-healing e-tongue.

Main Results:

• Successful creation of thin film composites with tunable electrical, mechanical, and structural characteristics.
• Demonstration of a delicate balance required for controlled design of conductive self-healing composites.
• The self-healing e-tongue sensor effectively distinguished basic tastes and detected trace glucose levels in artificial sweat.

Conclusions:

• LbL assembly provides a versatile platform for creating conductive self-healing thin films by incorporating various conductive fillers.
• The developed nanostructures offer smart coverage solutions for current technological challenges in electronics and sensing.
• The proof-of-concept e-tongue highlights the potential of these materials for advanced sensory applications.