Abstract Polyvinylidene fluoride (PVDF) hollow fiber membranes were developed by the thermally induced phase separation (TIPS) process using a triple-orifice spinneret with solvent co-extrusion at the outermost channel for applications in membrane distillation (MD). The polymer surface concentration during membrane preparation was controlled by exploiting the interfacial interactions of the diluent and polymer at the extruded solvent surface. The membrane surface was controlled from a dense to a porous structure with a large pore size and a high porosity, which considerably enhanced the membrane water vapor permeability to 13.5 L m−2 h−1. Furthermore, the solvent co-extrusion was responsible for the formation of surface spherulites with different shapes, such as contacted spherulites, isolated spherulites, and isolated spherulites with humps. The spherulites with humps constructed a novel hierarchical structure, which created a superhydrophobic surface that conferred upon the PVDF membrane a remarkable wetting resistance in the MD process toward low-surface-tension saline water. More significantly, all the unique structures were achieved using the one-step membrane fabrication process of solvent co-extrusion without additional processes and materials. Thus, this work provides a new, simple, and useful alternative for the preparation of hollow fiber membranes with high performances for MD desalination.

中文翻译：

---

通过使用三孔喷丝板进行膜蒸馏的热诱导相分离开发的具有分级球晶表面结构的中空纤维膜

摘要 聚偏二氟乙烯 (PVDF) 中空纤维膜是通过热致相分离 (TIPS) 工艺开发的，使用三孔喷丝头，在最外层通道使用溶剂共挤出，用于膜蒸馏 (MD)。通过利用稀释剂和聚合物在挤出溶剂表面的界面相互作用来控制膜制备过程中的聚合物表面浓度。膜表面由致密结构控制为大孔径、高孔隙率的多孔结构，使膜的水蒸气渗透率显着提高至13.5 L m-2 h-1。此外，溶剂共挤出是形成具有不同形状的表面球晶的原因，例如接触球晶、孤立球晶和带有隆起的孤立球晶。带有驼峰的球晶构成了一种新型的分层结构，它创造了一个超疏水表面，使 PVDF 膜在 MD 过程中对低表面张力盐水具有显着的润湿阻力。更重要的是，所有独特的结构都是使用溶剂共挤出的一步膜制造工艺实现的，无需额外的工艺和材料。因此，这项工作为制备用于 MD 脱盐的高性能中空纤维膜提供了一种新的、简单的和有用的替代方法。所有独特的结构都是使用溶剂共挤出的一步膜制造工艺实现的，无需额外的工艺和材料。因此，这项工作为制备用于 MD 脱盐的高性能中空纤维膜提供了一种新的、简单的和有用的替代方法。所有独特的结构都是使用溶剂共挤出的一步膜制造工艺实现的，无需额外的工艺和材料。因此，这项工作为制备用于 MD 脱盐的高性能中空纤维膜提供了一种新的、简单的和有用的替代方法。