Electrically Conducting Elastomeric Fibers with High Stretchability and Stability

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Stretchable conducting materials are crucial for unobtrusive wearable electronics.
• Conjugated polymers with oligoethylene glycol side chains offer low elastic modulus and good compatibility with polar polymers.

Purpose of the Study:

• To develop highly stretchable and conductive elastomeric blend fibers.
• To investigate the properties and potential applications of these novel fibers.

Main Methods:

• Wet spinning of a blend of doped polar polythiophene with tetraethylene glycol side chains and polyurethane.
• Chemical doping with iron(III) p-toluenesulfonate hexahydrate.
• Characterization of fiber properties including stretchability, conductivity, and cyclic stability.

Main Results:

• Continuous fibers (30-70 µm diameter) with high stretchability (up to 480%) and electrical conductivity (up to 7.4 S cm⁻¹).
• Fibers maintain conductivity during elongation and exhibit excellent long-term stability.
• High cyclic stability demonstrated through 400 strain cycles at 50% strain.
• Demonstration of a directional strain sensing device utilizing the fiber's resistance change.

Conclusions:

• The developed fibers represent a record combination of stretchability and conductivity for conjugated polymer-based materials.
• These fibers are promising for advanced wearable electronic devices and strain sensing applications.
• The wet-spinning process offers a versatile, scalable method for producing these functional fibers.