Tuning Ferroelectricity in PVDF-TrFE through Thermal Treatment-Dependent Crystal Orientation

Area of Science:

• Materials Science
• Polymer Science
• Solid State Physics

Background:

• Ferroelectric properties of poly-(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) films are strongly linked to molecular orientation.
• The dipole-electric field match problem necessitates precise control over film structure.

Purpose of the Study:

• To investigate how recrystallization temperature and cooling rate affect crystal orientation and ferroelectric performance in PVDF-TrFE thin films.
• To explore the role of mica substrates in melt recrystallization of PVDF-TrFE.

Main Methods:

• Melt recrystallization of PVDF-TrFE thin films on mica substrates.
• Characterization using 2D grazing incidence wide-angle X-ray diffraction (2D-GIWAXD).
• Surface morphology analysis via atomic force microscopy (AFM).
• Chemical structure analysis using Fourier transform infrared-grazing incidence reflection absorption spectroscopy (FTIR-GIRAS).
• Ferroelectric property evaluation through polarization-electric field (P-E) hysteresis measurements.

Main Results:

• Recrystallization at lower temperatures (25 °C) and faster cooling rates (100 °C/min) promote edge-on lamellar structures.
• Mica substrates enhance the formation of edge-on lamellae compared to glass or silicon.
• Optimized conditions lead to improved ferroelectric performance.

Conclusions:

• Lower recrystallization temperatures and faster cooling rates are effective in modulating PVDF-TrFE crystal orientation.
• Mica substrates offer a pathway to enhance edge-on lamellar formation for improved ferroelectric properties.
• This study provides a method to tune ferroelectric characteristics of PVDF-TrFE films via melt processing on mica.