基于HBPs接枝的PVDF膜亲水改性及抗污染性能

在聚偏氟乙烯（PVDF）微滤膜表面接枝超支化聚合物聚乙烯亚胺（HPEI），并通过环氧丙醇与氨基的开环反应在PVDF膜表面形成高密度的多羟基结构，实现PVDF膜的亲水改性.实验对膜的表面亲水性、抗粘附性能和抗污染性能进行表征，并采用原子力显微镜（AFM）测量膜与污染物探针之间的粘附力以进一步探究改性膜的抗污染机理.实验结果显示，改性后，PVDF膜的接触角从85°减小至42°，润湿时间从20s缩短至10s，表面亲水性显著提高；在静态吸附实验中，改性膜表面粘附的蛋白质和多糖数量明显减少；在动态污染实验中，改性膜的水通量恢复率（FRR）较高，不可逆通量下降率（IFR）较低，说明其较强的抗污染性能.AFM界面粘附力的测试结果表明污染物探针与改性膜面的粘附力较弱，进一步证实改性膜表面丰富的亲水基团以及超支化结构的位阻效应可以有效改善PVDF膜的抗污染性能.

Hydrophilic modification of PVDF membrane based on HPBs and its antifouling properties

Hyperbranched polyethyleneimine (HPEI) was grafted on the surface of polyvinylidene fluoride (PVDF) microfiltration membrane, and a high-density hydroxyl structure was formed on the surface of PVDF membrane by the ring-opening reaction of glycidol and the terminal amino groups. Contact angle tests confirmed the improved hydrophilicity of the modified membrane. After modification, the contact angle of PVDF membrane was decreased to 42° with initial 85° and the wetting time was shortened to 10s with initial 20s. Static adsorption tests demonstrated that the modified membrane had much less amount of proteins and polysaccharides on the membrane surface compared to the control. Dynamic fouling experiments showed that the modified membrane had significantly higher water flux recovery ratio and lower relative fouled flux ratio in comparison with the pristine PVDF membrane. AFM (Atomic Forces atomic force microscopy) contact force measurements exhibited weaker foulant-membrane interactions and foulant-foulant interactions for the modified membrane, which can be attributed to the abundant hydrophilic groups on the membrane surface and steric effect of the hyperbranched structure.