The influences of polydopamine immersion time on characteristics and performance of polyvinylidene fluoride ultrafiltration membrane

The Polyvinylidene Fluoride (PVDF) membrane has been prepared by phase inversion method using N,N-dimethylacetamide (DMAc) as solvent and Poly Ethylene Glycol (PEG) as additive. The fabricated membrane was modified by Polydopamine (PDA) coating in concentration of 0.5 mg/ml and immersion times of 2 hours, 6 hours, and 24 hours. The characteristics and performance of the PVDF membranes before and after the modification are studied in this paper. The result of the water flux experiment showed that the PDA-coated PVDF membranes showcased a higher flux than that of pure PVDF membrane. Scanning Electron Microscopy (SEM) analysis confirmed that the membrane had an asymmetric structure consisting of two layers. There was no significant influence on the addition of PDA to the morphology of the pore matrix because the modification was done by surface coating. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that PDA was successfully introduced on the surface of PVDF membrane with the appearance of O-H from cathecol and N-H peaks at wavenumber range of 3300-3600 cm-1. Modification with PDA increased the mechanical strength of the membrane which affirmed by the results of the tensile and elongation at break evaluation.