Engineering polydopamine-glued sandwich-like nanocomposites with antifouling and antibacterial properties for the development of advanced mixed matrix membranes

Abstract

Nanofillers play a critical role in the fabrication of mixed matrix membranes (MMMs) with superior properties. However, most nanomaterials are plagued with the poor dispersibility in membrane casting solution, which leads to compromised membrane performances. In this work, we have developed a facile method for engineering the nanomaterials with excellent capabilities though PDA coating and electroless silver plating. Taking carbon nanotubes (CNTs), halloysite nanotubes (HNTs) and cellulose nanocrystallines (CNCs) as examples, we have demonstrated that silver nanoparticles (AgNPs) could be uniformly coated on the surfaces of these nanomaterial. In contrast to their pristine counterparts, both the PDA-coated and AgNPs-decorated nanomaterials could be finely dispersed in membrane casting solutions. Consequently, they could be uniformly distributed in the polyvinylidene fluoride (PVDF) matrices of the membranes. All MMMs showed excellent antifouling properties with flux recovery rates over 80%. The best membrane was the one prepared with AgNPs-decorated CNTs as nanofillers (#Ag-CNT-P), which exhibited a 1.5-fold higher water flux without compromising bovine serum albumin (BSA) rejection. Noteworthy, this membrane also exhibited the best bactericidal property against E. coli attributed to the synergy between CNTs and AgNPs. Our work offered a feasible and versatile strategy to engineer nanomaterials as nanofillers for fabricating advanced MMMs.