Antifouling PVDF membranes fabricated via progressive potassium ion-π assembly of dopamine

Mussel-inspired surface modification draws a lot of attention for improving membrane antifouling property. However, it remains a serious challenge to fabricate a strong hydrophilic layer on the rough surface, preventing the pollutants to adhere to them during the filtration process. Here, a progressive cation-pi assembly of poly dopamine (PDA) was introduced to boost the antifouling property of the rough polyvinylidene fluoride (PVDF) membrane, which was fabricated by the non-solvent induced phase separation (NIPS) method using alcohol as the non-solvent. Afterward, dopamine and 3-sulfopropyl methacrylate potassium salt (SMPS) were co-deposited on the rough membranes via K+-pi interactions, leading to > 20% increment in graft yield compared with DA layer at the same deposition time. In addition, spin-spin relaxation time (T-2) of water of DS modified membrane characterized by relaxation NMR decreased 484.9 ms, revealing strong hydration capability on the membrane surface and excellent water hydrophilicity. Benefited by the hydration capability, improved antifouling performance was obtained against natural organic polymers and crude oil, and good oil-in-water emulsions separation property without pressure. The K+-pi interactions assistance dopamine assembly indicated a convenient technique for improving the antifouling performance of the rough membrane with a thick and strong hydrophilic layer.

Automated summary

Progressive cation-pi assembly of poly dopamine (PDA) was introduced to enhance the antifouling property of rough membranes. The assembly formed a strong hydrophilic layer, improving the hydration capability and antifouling performance of the membrane.