Ultrafiltration Membranes Coated by Amphiphilic Copolymers Containing Superhydrophilic Zwitterionic and Hydrophobic POSS Moieties Showing Improved Fouling Resistance/Release Properties

Ultrafiltration membranes coated with amphiphilic copolymers containing superhydrophilic zwitterionic moieties and hydrophobic POSS moieties (PSM‐coated membranes) are prepared. The free radical polymerization of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and 3‐(3,5,7,9,11,13,15‐heptaisobutylpentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane‐1‐yl)propyl methacrylate (MAPOSS) monomers is used to prepare a series of copolymers containing different compositions of DMAEMA and MAPOSS units (PDMs). The DMAEMA units in the PDM‐coated membranes are subsequently converted to sulfobetaine methacrylate (SBMA) units using 1,3‐propane sultone (post‐zwitterionization) to give the PSM‐coated membranes. The PSM‐coated membranes show improved fouling resistance/release properties, compared with a neat polysulfone (PSf) membrane. The improved fouling resistance properties of the PSM‐coated membranes are attributed to the superhydrophilic zwitterionic moieties, which form a hydration layer on the membrane surface via electrostatic interactions between the zwitterions and water molecules. Moreover, the total surface energy (γS) value of the PSM‐coated membrane is smaller than that of the PSf membrane due to the hydrophobic POSS moieties. This results in the superior fouling release properties of the PSM‐coated membranes. This work reports an ultrafiltration membrane coated with amphiphilic copolymers containing superhydrophilic zwitterionic and hydrophobic POSS moieties having promising fouling resistance/release properties. The superhydrophilic zwitterionic moieties forming a hydration layer on the membrane surface, and the hydrophobic POSS moieties having low surface energy improve fouling resistance/release properties, respectively.