In-situ construction of superhydrophobic polyvinylidene fluoride (PVDF) membrane was prepared through nonsolvent induced phase inversion process for direct contact membrane distillation (DCMD). Saturated sodium chloride aqueous solution (NaCl-H₂O) was added to the casting solution as a green phase inversion inducing agent. The variation of polymer crystal and the formation mechanism of micro-nano structure on membrane surface were studied. The results showed that NaCl crystals could act as nucleus for the pre-gelation and crystallization of PVDF chains. The “harsh” nonsolvent, water, accelerated the gelation process. When the optimum amount of NaCl-H₂O was added, superhydrophobic membrane with lotus leaf like micro-nano spherical structure and interconnected channels was obtained. The pure water contact angle reached 155.3° with DCMD flux of 54.5 L/m²∙h, which was about 1.6 times for the membrane without NaCl-H₂O addition. The stability was also improved owing to the superhydrophobic structure.

超疏水聚偏二氟乙烯（PVDF）膜的原位构建是通过非溶剂诱导相转化过程制备的，用于直接接触膜蒸馏（DCMD）。将饱和氯化钠水溶液（NaCl-H ₂ O）添加到浇铸溶液中作为生相转化诱导剂。研究了聚合物晶体的变化和膜表面微纳米结构的形成机制。结果表明，NaCl晶体可以作为PVDF链预凝胶化和结晶的核。“苛刻”的非溶剂水加速了凝胶化过程。当 NaCl-H ₂的最佳用量为添加O，获得了荷叶状微纳米球形结构和相互连接的通道的超疏水膜。纯水接触角达到155.3°，DCMD通量为54.5 L/m ² ∙h，约为未添加NaCl-H ₂ O的膜的1.6倍。由于超疏水结构，稳定性也得到了提高。