Abstract Until now, getting non-porous pure PVDF in the piezoelectric β-phase involved the application of stresses that limit the production of piezoelectric films into a flat form. In this work we present a new method to obtain, directly from the melt, pure β-PVDF which also allows the production of films with a 3D shape. A hydrophilic ionic liquid (IL), C2mim BF4, is used to totally induce the direct crystallization of PVDF in the piezoelectric β-phase during the melt. Afterwards, this IL is completely removed by washing the film in water at 70 °C. The process results in the production of a non-porous pure PVDF film, totally crystallized in the β-phase. Finally and for the first time, the replication of a 3D shape given by a glass form could be demonstrated by using this polymer.

中文翻译：

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在压电 β 相中直接制造 3D 形状的聚偏二氟乙烯 (PVDF) 薄膜，用于传感器和执行器应用

摘要 迄今为止，在压电 β 相中获得无孔的纯 PVDF 涉及施加应力，这些应力限制压电薄膜的生产成为平面形式。在这项工作中，我们提出了一种直接从熔体中获得纯 β-PVDF 的新方法，该方法也允许生产具有 3D 形状的薄膜。亲水性离子液体 (IL) C2mim BF4 用于在熔化过程中完全诱导 PVDF 在压电 β 相中的直接结晶。之后，通过在 70 °C 的水中洗涤薄膜来完全去除该 IL。该过程导致生产无孔的纯 PVDF 薄膜，完全在 β 相中结晶。最后，也是第一次，可以通过使用这种聚合物来演示由玻璃形式给出的 3D 形状的复制。