Different Crystallization Behaviors of Poly(vinylidene fluoride) Blended with or Coated with Cetyltrimethylammonium Bromide

• Published in: Macromolecules 2023-10, Vol.56 (20), p.8214-8221
• Main Authors: Nie, Yongjia, Zhao, Wenpeng, Chen, Xu, Zhang, Hao, Hu, Jian, Wang, Shaojuan, Yan, Shouke
• Format: Article
• Language: English
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/acs.macromol.3c01466

Crystallization of poly­(vinylidene fluoride) (PVDF) either blended with or coated with cetyltrimethylammonium bromide (CTAB) during isothermal and nonisothermal processes has been studied, which reveals the influence of the interaction way between PVDF and CTAB on the polymorphic behavior of PVDF. The random dispersion of CTAB with limited content in the blend sample leads to three different states of PVDF chains, i.e., intact chains and TGTG′ and TTT chain sequences induced by the ion–dipole interaction. While the intact chains and TGTG′ sequences promote the crystallization of PVDF in the α-phase, the TTT chain sequences cause the crystallization of PVDF in the γ-phase at high temperatures, which endows a full transformation of α into γ′ at the later stage. On the other hand, for the PVDF coated with CTAB, the ion–dipole interaction results in the long TTT sequences, or even all-trans chain segments, at the interface between PVDF and CTAB, which ensure the crystallization of PVDF directly in the γ-phase at high temperatures but in the β-phase during melt-quenching. This provides a simple and effective method for fabricating high-crystallinity (e.g., 47%) electroactive PVDF thin films with a preferential β-phase of ca. 95.3% and a small amount of γ-phase (around 4.7%).