Synergistic Flow Field and Ion-Dipole Interactions Enable γ-β Phase Transformation in Poly(vinylidene fluoride)

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Poly(vinylidene fluoride) (PVDF) possesses excellent piezoelectric properties dependent on polar phase content and orientation.
• Achieving highly oriented polar phases in PVDF is crucial for advanced piezoelectric applications.

Purpose of the Study:

• To develop a synergistic strategy for highly oriented β phase in PVDF using flow fields and ion-dipole interactions.
• To investigate the combined effects of solid-phase extrusion and CTAB on PVDF phase transformation and hierarchical structure.

Main Methods:

• Designed a solid-phase extrusion die to induce a converging flow field.
• Incorporated Cetyltrimethylammonium Bromide (CTAB) to introduce ion-dipole interactions.
• Analyzed PVDF phase transformation, molecular chain alignment, and lamellar structure evolution.

Main Results:

• CTAB incorporation promoted γ phase formation, serving as a precursor for γ-β transformation.
• The converging flow field during extrusion induced extensive molecular chain alignment and enhanced β phase content and orientation.
• Optimal performance was observed in PVDF blends with 5 wt% CTAB, showing superior polar phase characteristics and dielectric constant.

Conclusions:

• A synergistic strategy combining flow-induced fields and ion-dipole interactions effectively regulates PVDF hierarchical structures.
• This method provides an effective route for fabricating high-performance piezoelectric PVDF materials with enhanced properties.