Thermally Stable Poly(vinylidene fluoride) for High-Performance Printable Piezoelectric Devices

Area of Science:

• Materials Science
• Polymer Chemistry
• Ferroelectric Materials

Background:

• Piezoelectric polymers like poly(vinylidene fluoride) (PVDF) are crucial for electronic devices and intelligent structures due to their large strain and high work density.
• Traditional processing of PVDF can limit its piezoelectric performance and processing temperature range.

Purpose of the Study:

• To investigate dehydrofluorination (DHF) as a versatile chemical modification for PVDF homopolymers.
• To enhance the piezoelectric properties and thermal stability of PVDF.
• To enable new manufacturing processes for PVDF-based devices.

Main Methods:

• Chemical modification of PVDF via dehydrofluorination (DHF).
• Molecular simulation to understand chain conformation changes.
• Experimental characterization to verify structural and piezoelectric properties.
• High-temperature treatments to assess thermal stability.

Main Results:

• DHF significantly increases the fraction of planar chain conformation in PVDF, enhancing piezoelectric coupling.
• The modified PVDF exhibits ferroelectricity and retains it after high-temperature treatment (up to 200 °C).
• Achieved a high piezoelectric strain coefficient (d31) of 25.12 ± 1.13 pC/N, further improved to 35.12 ± 0.69 pC/N with mechanical drawing.
• Demonstrated excellent actuation and energy harvesting with a power density of 21.96 mW/cm³ in a flexible energy harvester.

Conclusions:

• Dehydrofluorination is an effective method for creating thermally stable, ferroelectric PVDF with superior piezoelectric properties.
• The enhanced PVDF offers significant improvements in electromechanical coupling and energy harvesting capabilities.
• This scalable DHF method expands manufacturing possibilities for PVDF homopolymers in advanced applications.