Fabrication of ionic liquid-functionalized polystyrene nanospheres via subsurface-initiated atom transfer radical polymerization for anti-fouling application

The chemical and biological characteristics of ionic liquids (IL) can be engineered via a suitable selection of their constituent anions and cations, which is instrumental in the research and the development of anti-biofouling materials. The ring-opening reaction and subsurface-initiated atom transfer radical polymerization (sSI-ATRP) were employed to prepare IL-functionalized polystyrene nanospheres effectively. The sSI-ATRP was used to graft the poly(glycidyl methacrylate) (PGMA) brushes onto crosslinked polystyrene (CPS) nanospheres while they were fully swollen. Subsequently, the imidazolium-based IL was bound onto PGMA brushes through ring-opening reaction between the epoxide groups of PGMA and the amine groups of IL. Furthermore, their anti-wear, antibacterial, and antifouling properties were comprehensively evaluated. Experimental results reveal that the as-prepared IL-functionalized PS nanospheres exhibited good antibacterial properties against both E. coli and S. aureus, attributable to the imidazole groups of IL, in addition to resisting adhesion of Porphyridium and Dunaliella. Moreover, the IL-functionalized CPS nanospheres manifested satisfactory wear resistance as against the traditional surface-initiated atom transfer radical polymerization (SI-ATRP), because the PGMA can graft on the surface and subsurface of the polystyrene nanospheres via sSI-ATRP. The as-obtained IL-functionalized polystyrene nanospheres can be mixed effectively with the self-polishing resin to acquire a novel self-polishing nanocomposite coating, the nanocomposite coating exhibit good antibacterial characteristics against E. coli and S. aureus, as well as a substantial antifouling effect against microalgae (83 % Porphyridium and 85 % Dunaliella were removed).