Deep Eutectic Solvent—A Novel Additive to Induce Gamma Crystallization and Alpha‐to‐Gamma Phase Transition of PVDF

• Published in: Macromolecular chemistry and physics Vol. 223; no. 4
• Main Authors: Yuan, Muhua, Wang, Haijun, Li, Huihui, Yuan, Chunlei, Wang, Tong, Yang, Haibo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.02.2022
• Subjects: Additives; Crystallization; Crystals; deep eutectic solvent; Dielectric properties; Dipole interactions; dispersion; Gamma phase; Hydrogen bonds; ion–dipole interaction; Molecular conformation; phase transition; Phase transitions; Piezoelectricity; poly(vinylidene fluoride); Polyvinylidene fluorides; Solvents; Vinylidene fluoride
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.202100416

Adding additives is the most convenient and effective way to induce polar poly(vinylidene fluoride) (PVDF) crystals which exhibit excellent ferroelectronic, piezoelectric, and dielectric properties. In this work, a kind of environmentally friendly additive, deep eutectic solvent (DES), is introduced to induce the crystallization of polar phases and accelerate the α‐to‐γ phase transition, which enables the fraction of γ(γ′)‐phase crystals to exceed 90% in the PVDF/DES composite containing only 1 wt% DES. The ion–dipole interaction between PVDF and hydrogen bond acceptor in DES induces the polar molecular conformation, thus bringing about the formation of polar phase crystals. However, hydrogen bond donor promotes the dispersion of hydrogen bond acceptor in PVDF matrix, contributing to the flexibility of the composites. Deep eutectic solvent (DES) is introduced to induce the crystallization of γ‐PVDF and accelerate the α‐γ phase transition. The ion–dipole interaction between the hydrogen bond acceptor in DES and PVDF induces the polar molecular conformation, while hydrogen bond donor promotes the dispersion of hydrogen bond acceptor in PVDF matrix, contributing to the flexibility of the composites.