Abstract The preparation of poly(vinylidene fluoride) (PVDF) membranes with high mechanical strength via vapor-induced phase separation (VIPS) is still a great challenge. In this study, high strength PVDF membranes with cellular pore structure are successfully prepared by comprehensively regulating the process parameters such as the dissolution temperature (Td), vapor temperature (Tv) and exposure time (t) during the VIPS process, as well as the membrane-forming parameter i.e. mass fraction of PVDF polymer. The effects of these parameters on microstructure and performances of the PVDF membranes are systematically investigated. In the investigated ranges of t from 0.67min to 20 min, the membranes with cellular structure are obtained at both elevated Td and Tv of 65 °C, relative humidity of 70%RH and mass fraction of 15 wt% PVDF. All the PVDF membranes with cellular structure prepared at elevated Td and Tv of 65 °C exhibit high mechanical properties, and the tensile stress at break (σ*) and tensile strain are higher than 2.5 MPa and 15%, respectively. The PVDF membrane prepared at t of 0.5 min has a critical structure and shows the maximum σ* of 4.0 MPa and tensile strain of 33%, respectively. It is expected that the results provide a valuable guidance for the design and fabrication of membranes from semi-crystalline polymer with desirable performances.

中文翻译：

---

气相诱导相分离制备具有蜂窝结构的高强度聚偏二氟乙烯多孔膜

摘要 通过气相诱导相分离（VIPS）制备具有高机械强度的聚偏二氟乙烯（PVDF）膜仍然是一个巨大的挑战。本研究通过综合调控VIPS过程中的溶解温度（Td）、蒸气温度（Tv）和暴露时间（t）等工艺参数，以及成膜参数，即 PVDF 聚合物的质量分数。系统地研究了这些参数对 PVDF 膜的微观结构和性能的影响。在 t 从 0.67 分钟到 20 分钟的研究范围内，在 65°C 的升高的 Td 和 Tv、70%RH 的相对湿度和 15 wt% PVDF 的质量分数下获得具有蜂窝结构的膜。在 65°C 升高的 Td 和 Tv 下制备的所有具有蜂窝结构的 PVDF 膜都表现出较高的机械性能，断裂拉伸应力 (σ*) 和拉伸应变分别高于 2.5 MPa 和 15%。在 t 为 0.5 分钟时制备的 PVDF 膜具有临界结构，最大 σ* 分别为 4.0 MPa 和拉伸应变为 33%。预计结果为设计和制造具有理想性能的半结晶聚合物膜提供有价值的指导。0 MPa 和拉伸应变分别为 33%。预计结果为设计和制造具有理想性能的半结晶聚合物膜提供有价值的指导。0 MPa 和拉伸应变分别为 33%。预计结果为设计和制造具有理想性能的半结晶聚合物膜提供有价值的指导。