Superhydrophilic polymer coatings based on PVDF membranes for oil-water separation

Recently, the excellent anti-pollution performance of superhydrophilic membrane has attracted much attention in the field of wastewater treatment and oil-water separationIn. At present, the widely used commercial membrane materials have good pore structure and mechanical properties, but most of the commercial membranes are hydrophobic, so a simple, environmentally friendly and universal method is urgently needed to change its hydrophobic membrane to superhydrophilic membrane. In this paper, tannic acid (TA, natural plant polyphenols) and polydopamine (PDA) were used to build an anti-stain coating. The synthesized hydrophilic polymer containing polyphenols crosslinks with the base layer through hydrogen bonding, π-π and Michael addition. After the modified PVDF membrane is moistened by water, the superhydrophilic polymer network on the surface binds the water to form a stable hydration layer, showing the superhydrophilic/underwater superhydrophobic properties. The wettability of the modified film in air and water was investigated. The contact Angle of the modified separation membrane prepared in this paper is more than 150°, and the separation efficiency exceeded 98%. The good flux and efficiency can be maintained after 5 cycles, and it is found that the membrane has a certain anti-protein adsorption capacity. The modified membrane has high separation flux and excellent reuse, and has great uses in other ways.