Carbonized Electrospun Nanofiber Sheets for Thermophones

Area of Science:

• Materials Science
• Acoustics
• Nanotechnology

Background:

• Thermoacoustic devices, or thermophones, convert thermal energy into sound waves.
• Freestanding nanofiber sheets offer unique properties for advanced material applications.
• Carbonized polymers present a potentially cost-effective alternative to carbon nanotubes in thermophone technology.

Purpose of the Study:

• To evaluate the thermoacoustic performance of carbonized poly(acrylonitrile) and polybenzimidazole nanofiber sheets.
• To analyze the thermodynamic properties influencing energy conversion efficiency in these materials.
• To compare their performance with carbon nanotube sheets and theoretical models.

Main Methods:

• Characterization of electrical and thermal conductivities, thermal diffusivity, and heat capacity.
• Investigation of infrared blackbody radiation to determine the heat exchange coefficient.
• Analysis of sound pressure dependencies and comparison with carbon nanotube sheets.

Main Results:

• Carbonized polymer nanofiber sheets exhibit lower thermoacoustic performance than carbon nanotube sheets.
• These materials demonstrate advantages in the low-frequency domain (<1000 Hz) due to thermal diffusion length and high thermal conductivity.
• Mechanical strength and cost-effective production are significant advantages.

Conclusions:

• Carbonized electrospun polymer nanofiber sheets are attractive for large-size sound projectors, especially in the low-frequency range.
• Their properties make them suitable for applications in loudspeakers, SONAR arrays, and sound cancellation.
• Further development could enhance their thermoacoustic efficiency for broader applications.