Silver nanowire/thermoplastic polyurethane elastomer nanocomposites: Thermal, mechanical, and dielectric properties

• Young’s moduli and crystallinity of the AgNW/TPU nanocomposite films increased with AgNW content.
• Higher AgNW content induced higher dielectric constant while maintaining a low dielectric loss.
• The PVP AgNW coating affected the thermal and mechanical properties of the AgNW/TPU nanocomposites.

Films of polyvinylpyrrolidone (PVP)-stabilized silver nanowire (AgNW)/thermoplastic polyurethane (TPU) elastomer nanocomposites were fabricated and characterized. With increasing loading levels of AgNW, the transparency of the nanocomposite films was reduced, but their crystallization temperatures increased, suggesting that AgNW could serve as crystallization nucleating agents. The addition of AgNW also enhanced both the Young’s moduli and storage moduli of the nanocomposite films, but caused a reduction in their strain-at-break (from 536% to 304% with 1.5 vol.% AgNW) and ultimate strength (from 12.7 to 9.8 MPa with 1.5 vol.% AgNW). The specific toughness was the highest for nanocomposites with AgNW loading levels of 0.03 vol.% and 0.05 vol.%. In addition, the dielectric constant of the nanocomposite films with 1.5 vol.% AgNW was 9 times higher than that of pure TPU at 1 kHz, while the dielectric loss of all nanocomposite films studied was less than 0.2. Thus, AgNW/TPU elastomer nanocomposites with varying mechanical, dielectric, and thermal properties can be engineered by adding a small amount of AgNW. These nanocomposites can potentially be used for a wide range of applications including dielectric materials.