Deposition of polydopamine on the surface of Polyvinylidene Fluoride (PVDF) membrane as A UV-Shielding layer

This paper discusses about the influence of polydopamine layer in enhancing UV resistance of PVDF membrane for membrane photocatalytic reactor application. The PVDF membrane was prepared by common NIPS method using DMAc as a solvent and PEG as a pore-forming additive. The polydopamine layer was deposited on the membrane surface by the facile dip-coating method through Tris-buffered dopamine polymerization. The UV-shielding effect of PDA layer was studied by comparing the changes in pure and PDA coated membrane coating before and after UV irradiation. The studied effects are in terms of changes in chemical, morphological structure and mechanical properties which observed by means of ATR-FTIR, FESEM instrumental analysis, and tensile measurement, respectively. The IR analysis showed that after PDA coating, the membrane surface is rich of catecholamine groups which greatly contributed as free radical scavengers. The change in chemical structure was seen on pure membrane which attributed to the rearrangement of polymer chemical structure caused by UV-induced photodegradation. FESEM imaging results showed that with PDA coating the membrane surface showed minimal damage in comparison to that of non-coated PVDF membrane. These results altogether confirmed, that the PDA layer can protect the membrane surface from UV-initiated free radicals attack.