Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance

Abstract

Novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes were facilely fabricated using polyvinyl alcohol (PVA) aqueous solution as the coagulation bath through phase inversion method. In the process, PVA was introduced into the pore surfaces of the PVDF membranes via the interdiffusion of the non‐solvent water and the solvent. The effects of PVA content in the coagulation bath on membrane properties were systematically discussed. The results indicated that the increase of PVA content in coagulation bath resulted in the formations of the more sponge‐like structures and the higher surface hydrophilicity. Smaller pore size led to lower water flux and higher bovine serum albumin rejection. Fouling resistance measurement indicated that the membranes made in PVA/water coagulation bath had higher flux recovery ratio (92.1%) than the membrane made in a pure water bath (71.0%). Furthermore, mechanical property test revealed that the resulting membranes had high tensile strength and Young's modulus. In this work, we found that the morphology and the property of the novel PVDF membranes could be determined by the PVA content in the coagulation bath. POLYM. ENG. SCI., 59:E384–E393, 2019. © 2018 Society of Plastics Engineers

Improving the Performance of PVDF/PVDF-g-PEGMA Ultrafiltration Membranes by Partial Solvent Substitution with Green Solvent Dimethyl Sulfoxide during Fabrication

“…Poly­(vinylidene) fluoride (PVDF) is a well-established polymeric material to produce ultrafiltration (UF) and microfiltration (MF) membranes owing to its exceptional mechanical properties, chemical resistance, and thermal stability. − However, despite its many advantages, the hydrophobicity of PVDF can induce severe membrane fouling, which is a main obstacle that limits its applications. − Thanks to the compatibility of the PVDF matrix with amphiphilic copolymers, modifications of PVDF membranes by blending with other more hydrophilic components have been reported widely. − The atom transfer radical polymerization (ATRP) method can be applied to enhance the properties of polymers by grafting chains with different characteristics, making the preparation of many new copolymers possible. − Specifically, PVDF- graft -poly­(ethylene glycol) methyl ether methacrylate (PVDF- g -PEGMA) has been successfully synthesized and characterized. ,, Membranes with promising fouling resistance behavior were thus produced by blending this PVDF- g -PEGMA material with traditional PVDF …”

Effect of the Addition of Polyacrylic Acid of Different Molecular Weights to Coagulation Bath on the Structure and Performance of Polysulfone Ultrafiltration Membranes

“…This technique can contribute to surface modification due to the embedding of hydrophilic polymers or polyelectrolytes into the selective layer, which yields changes in the hydrophilicity, roughness, charge and chemical composition of the membranes. This approach was developed and studied in [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ].…”

“…Polyacrylic acid (PAA) [ 48 , 49 , 53 ], polyethylene imine (PEI) [ 37 , 41 , 43 ], copolymers Praestol 859 [ 47 , 51 ] and Praestol 2540 [ 50 ], poly (diallyldimethylammonium chloride) [ 41 ], chitosan [ 55 ], zwitterionic copolymers [ 56 ], poly (sodium 4-styrenesulfonate) (PSS) [ 40 ], PVP [ 52 ] and PVA [ 54 ] were applied as additives to the coagulant for preparation of flat-sheet and hollow fiber membranes. There are different purposes which can be achieved by the addition of hydrophilic polymers and polyelectrolytes to precipitation medium: Increase in membrane antifouling performance [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 56 ]; Formation of a separation layer after subsequent cross-linking [ 37 , 38 ] or reaction with oppositely charged polyelectrolyte [ 37 , 40 , 41 , 42 , 45 , 46 ]; Creating an intermediate layer for preparation of the composite membrane via interfacial polymerization (IP) technique [ 44 ]; Tailoring membrane surface charge for enhanced separation of charged molecules [ 39 ]. …”

“…In [ 54 ], an aqueous solution of PVA was applied as a surface hydrophilizing agent for polyvinylidene fluoride (PVDF) ultrafiltration membrane modification during its preparation via the NIPS technique. It was revealed that membrane precipitation in the PVA aqueous solution led to the enhanced surface hydrophilicity manifested in the water contact angle decrease from 72° to 53°.…”