Boosting the visible-light-driven photocatalytic antibacterial performance of MoS2 nanosheets by poly(3-(4-methyl-3′-thiophenoxy))propyltrimethylammonium chloride (PThM) modification

Abstract

Molybdenum disulfide (MoS₂) has been reported to possess photocatalytic bactericidal ability, but its efficiency is not high. In this paper, a water-soluble cationic conjugated polymer, poly(3-(4-methyl-3′-thiophenoxy))propyltrimethylammonium chloride (PThM), was designed to modify MoS₂ and boost its antibacterial abilities. Another hydrophobic conjugated polymer, polythiophene (PTh), was synthesized and composited with MoS₂, and this was compared with PThM/MoS₂ from the perspective of composite effectiveness. Studies involving the photo-disinfection of Escherichia coli (E. coli) under visible-light irradiation (30 W) showed that the antibacterial efficiencies were in the following order: PThM/MoS₂ > PTh/MoS₂ > MoS₂. The enhanced bactericidal activities of PThM/MoS₂ and PTh/MoS₂ were attributed to the conjugated polymers restraining the recombination of photogenerated carriers in MoS₂, thereby increasing the generation of reactive oxygen species (ROS). PThM/MoS₂ presented the best antibacterial efficiency because its cationic side-chains improved the solubility of the material and promoted contact between bacteria and the material. This work may provide some insights into the design of practical nano-antibacterial materials.