β Phase Optimization of Solvent Cast PVDF as a Function of the Processing Method and Additive Content.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Poly(vinylidene fluoride) (PVDF) is a semicrystalline polymer with notable piezo-, pyro-, and ferroelectric properties.
• The β phase polymorph of PVDF exhibits superior piezoelectric characteristics, crucial for advanced applications.
• Enhancing the β phase content is key to maximizing PVDF's functional performance.

Purpose of the Study:

• To investigate methods for inducing and enhancing the β phase transformation in PVDF.
• To explore the effects of various processing techniques and additives on PVDF's β phase content.
• To analyze the dielectric and mechanical properties of modified PVDF composites.

Main Methods:

• Investigated annealing, uniaxial stretching, rolling, atmospheric plasma, and UV treatments.
• Processed PVDF composites with multiwalled carbon nanotubes and barium titanate (modified/unmodified).
• Characterized phase transformation using Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry.

Main Results:

• Stretching following solvent casting and hot pressing yielded the most significant α to β phase transformation in PVDF.
• Combinations of processing methods and the inclusion of additives effectively influenced the β phase content.
• Rolled PVDF polymer composite films showed variations in tan δ, elastic, and loss modulus values.

Conclusions:

• Processing techniques and additive incorporation are critical for controlling PVDF's β phase content and properties.
• Optimized processing can significantly enhance the piezoelectric performance of PVDF.
• Further research into PVDF composites can unlock advanced material functionalities.