辛醇对PVDF膜表面浸润性与透过性能的影响

以聚偏氟乙烯（PVDF）／N，N-二甲基乙酰胺（DMAc）／辛醇／水为制膜体系，采用干、湿相转化法制膜．考察了辛醇含量对膜结构、表面浸润性和透过性能的影响．结果表明，辛醇的加入使成膜过程中液．固分相在与液一液分相的竞争中占据优势，随着辛醇含量的增加，膜结构由海绵状结构向球晶堆积结构转变，当辛醇含量增至10％时，生成“菜花状”球晶粒子堆积的对称结构，其表面具有微纳二重特征，对水的接触角可达140°；实验范围内PVDF膜下表面的疏水性随铸膜液中辛醇含量的增加先增大后略有下降，膜的气通量随铸膜液中辛醇含量的增加先增大后减小所制得的高度疏水膜可望成为气液膜接触器的理想膜材料．

Effect of Octanol on Wettability and Permeability of PVDF Porous Membrane via Dry-Wet Phase Inversion

Hydrophobic polyvinylidene fluoride （PVDF）membranes were tailored by dry-wet phase inversion with the system of polyvinylidene fluoride （PVDF）AN, N-dimethylacetamide （DMAc）and octanol/water. The effects of octanol content on the morphology, wettability and permeability of PVDF membrene were investigated. PVDF is a semi-crystalline polymer, therefore, there exists the competition of liquid-liquid demixing and liquid-solid demix- ing. Adding octanol into the solvent made the liquid-solid demixing occupy the predominant position as competing with liquid-liquid demixing. The membrane morphologies transited from spongy structure to nodule-like structure with increasing octanol content. The membrane exhibited cauliflower-like spherulitic particles and symmetric morphologies when octanol content increased to 10%. The particles had a diameter of 5--10 μm and nanoscale papillas appeared on the particles. The micro- and nano-scale hierarchical roughness on the bottom surface brought about an enhanced hy- drophobicity of the membrane. The contact angle of the membrane with water was as high as 140° , exhibiting high hydrophobic property. In the experimental range, the water contact angle increased and then decreased slightly with increasing octanol content; the nitrogen flux increased and then decreased obviously with increasing octanol content. The well controlled structure makes these membranes ideal interfaces to be processed in membrane contactors.