Construct durable, antifouling double network hydrogel coatings on PTFE hollow fiber membranes via silane grafting

Polytetrafluoroethylene (PTFE) hollow fiber membranes are a promising candidate in highly contaminated wastewater treatment and management because PTFE is intrinsically chemically inert and hydrophobic. However, low water flux and fouling (contamination due to protein attachment and accumulation), both associated with low surface energy, pose great limits in filtration efficiency and the long-term use of PTFE hollow fiber membranes. Here we report a surface engineering strategy of coating PTFE hollow fiber membranes with polyvinyl alcohol/oxidized sodium alginate (PVA/OSA) double network (DN) hydrogels via N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTS) hydrolysis and grafting. The as-prepared PVA/OSA DN hydrogel coated PTFE hollow fiber membranes exhibited high efficiency in oil-water separation and excellent antifouling performance due primarily to the favorable interfacial electrostatic interaction and the hydration coating layer on the membrane surfaces. Moreover, the PVA/OSA DN hydrogel coatings remained high hydrophilicity and structural intergrity and operation stability after extensive time of soaking in strong acidic and alkaline solutions, all in great favor of the performance they were initially designed and intended for.