Carbon Nanotube-Polyurethane Composite Sheets for Flexible Thermoelectric Materials

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Single-wall carbon nanotubes (SWCNTs) offer exceptional properties but are challenging to integrate into composites.
• Preformed SWCNT assemblies like fabrics simplify handling and enable higher nanotube loadings for multifunctional materials.

Purpose of the Study:

• To develop p-type SWCNT-thermoplastic polyurethane (TPU) fabric materials.
• To tailor mechanical and thermoelectric properties by varying SWCNT content.
• To create easy-to-process, self-supporting, and stretchable materials for flexible thermoelectric devices.

Main Methods:

• A one-step filtration method was used to create SWCNT-TPU fabric materials.
• SWCNT suspensions in a TPU solvent/nonsolvent mixture were employed.
• SWCNT/TPU weight ratios were varied from 5 to 90 wt %.

Main Results:

• SWCNT-TPU nanocomposites exhibited significantly improved strength and stretchability compared to pristine SWCNT buckypaper.
• A 50/50 wt % SWCNT-TPU composite (15 vol % SWCNTs) achieved a power factor of 57 μW m⁻¹ K⁻², slightly exceeding SWCNT buckypaper (54 μW m⁻¹ K⁻²).
• This composite showed substantial mechanical enhancements: ~7-fold increase in stiffness, ~25-fold in strength, and ~250-fold in tensile toughness.

Conclusions:

• The developed SWCNT-TPU fabrics are promising for flexible thermoelectric applications.
• The materials offer a balance of robust mechanical properties and efficient thermoelectric performance.
• This work advances the development of processable, multifunctional nanocomposites.