Polyvinylidene Fluoride Aerogels with Tailorable Crystalline Phase Composition

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Polyvinylidene fluoride (PVDF) is a versatile fluoropolymer with diverse applications.
• Controlling the crystalline phase of PVDF is crucial for optimizing its properties.
• Aerogels offer unique structural properties due to their high porosity.

Purpose of the Study:

• To prepare PVDF aerogels with tailorable phase composition.
• To investigate the influence of non-solvent composition on PVDF aerogel crystallization and properties.
• To achieve specific crystalline phases (β and γ) for enhanced material performance.

Main Methods:

• Preparation of PVDF wet gels via crystallization-induced gelation using PVDF-DMF solutions and non-solvent mixtures (DMF/ethanol).
• Systematic variation of non-solvent concentration to control gelation and crystallization.
• Characterization using Fourier-transform infrared (FTIR) and Raman spectroscopies to monitor crystalline phases.
• In-situ ATR-FTIR spectroscopy to follow the crystallization process.
• Scanning electron microscopy (SEM) and Synchrotron Radiation Computed micro-Tomography (SR-μCT) for morphological analysis.

Main Results:

• PVDF aerogels with tailorable phase composition were successfully synthesized.
• Ethanol acted as a nucleating agent, enabling the production of low-density PVDF aerogels.
• Addition of water promoted the stabilization of the desirable β and γ PVDF phases.
• Specific surface areas exceeding 150 m² g⁻¹ were achieved.
• Aerogel morphology was found to be dependent on the non-solvent composition.

Conclusions:

• Crystallization-induced gelation is an effective method for preparing PVDF aerogels with controlled phase composition.
• Non-solvent engineering provides a pathway to tune the crystalline phases (β and γ) and properties of PVDF aerogels.
• The developed PVDF aerogels exhibit high surface area and tunable morphologies, indicating potential for various applications.