溶胀辊轧法PVDF膜表面的疏水强化：溶胀剂的影响

提出了一种简便、低成本的聚偏氟乙烯（PVDF）微孔膜表面疏水增强方法——溶胀辊轧法，以微结构辊筒对表面喷涂溶胀剂的PVDF成品微孔膜辊轧后，采用浸没凝胶法成膜。以N-甲基吡咯烷酮/水（非溶剂）为溶胀体系，采用扫描电子显微镜（SEM）、原子力显微镜（AFM）、水接触角（WCA）、最大孔径、平均孔径、N₂通量、耐磨性、液体穿透压（LEP）等表征手段，系统地研究了溶胀剂体系、溶胀剂容量对PVDF微孔膜结构与性能的影响。结果表明：辊轧膜表面呈现微米-亚微米层次特征，溶胀辊轧操作起到了疏水增强、透过能力提升的效果。溶胀剂中水（非溶剂）质量分数为6%、喷涂密度为0.03mL/cm²时，膜性能最优。连续运行30h的真空膜蒸馏（VMD）对比实验表明，辊轧膜较未辊轧膜具有更高的产水通量、脱盐率及更好的耐污染性能。该方法为低成本、连续化进行成品膜表面疏水强化提供了一种新选择。

Hydrophobic strengthening of the surface of PVDF membrane by swelling rolling: the influence of swelling agent

A simple and low-cost method for enhancing the hydrophobicity of PVDF microporous membrane surface——swelling embossed method was proposed. The membrane was made by immersion gel after rolling the PVDF microporous membrane with microstructure roller. The water (non-solvent) of N-methyl pyrrolidone was a swelling agent. The influence of the structure and properties of PVDF microporous membrane characterized by SEM, atomic force microscope (AFM), contact angle, maximum pore size, average pore size, N₂ flux, wear resistance and liquid entry pressure. The results indicated that the surface of the embossed membrane presented micron-submicron hierarchical features, the operation of swelling rolling had enhanced hydrophobicity and improved permeability, and thus had great hydrophobic stability. When the mass fraction of water (non-solvent) in the swelling agent was 6% and the spray density was 0.03mL/cm², the performance of the membrane was the best. The contrast experiment of continuous operation of 30h vacuum membrane distillation (VMD) showed that the embossed membrane had higher penetration flux and salt rejection rate and better pollution resistance than unembossed. This method provided a new option for low-cost and continuous hydrophobic strengthening of the surface of the finished membrane.