Development of highly robust polyurethane elastomers possessing self-healing capabilities for flexible sensors

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Traditional flexible electronic sensing materials face limitations in diverse applications and environments.
• There is a need for advanced, multi-functional elastomer materials to improve flexible electronic sensor performance and expand functionality.

Purpose of the Study:

• To fabricate a multi-block polyurethane (PU) elastomer with enhanced mechanical properties, self-healing, and recyclability.
• To investigate the influence of chain segment ratios on the elastomer's thermodynamic, hydrophobic, mechanical, and self-healing characteristics.
• To develop a flexible electronic sensor using the optimized PU elastomer as a matrix material.

Main Methods:

• Fabrication of a multi-block PU elastomer using semi-crystalline polycaprolactone (PCL) and polydimethylsiloxane (PDMS) segments.
• Tuning the ratio of PCL and PDMS segments to modulate material properties.
• Characterization of mechanical properties (tensile strength, elongation at break, toughness), self-healing efficiency, and recyclability.
• Encapsulation of conductive ink (PEDOT:PSS) within the elastomer to create a flexible electronic sensor.

Main Results:

• The optimized PU elastomer demonstrated high tensile strength (16.26 MPa), high elongation at break (3300.84%), and good toughness.
• Achieved near-perfect self-healing (≈100% at room temperature in 12 h) via dynamic disulfide, boron-oxygen, and hydrogen bonds.
• Exhibited efficient recyclability and puncture resistance.
• The resulting flexible electronic sensor showed excellent and stable sensing performance over 1000 cycles.

Conclusions:

• The developed multi-block PU elastomer offers a promising solution for next-generation flexible electronic sensors.
• The material's tunable properties, self-healing, and recyclability align with green electronic material concepts.
• This elastomer provides a versatile matrix for advanced applications in flexible electronics, robotics, and stimulus-responsive materials.