Mussel-inspired antimicrobial and antireflective Ag-NPs/PDA/SiO₂ coatings via interfacial functionalization

Utilizing surface chemical engineering to endow interfacial special functionalities is effective for fabricating antireflection coating with antibacterial activity. Herein, we present a mussel-inspired dopamine (DA) interfacial functionalization strategy to modify porous silica antireflection coatings, forming a sandwich composite structure composing an antireflective, intermediary, and antibacterial layer. The low refractive index antireflective coating formed by porous silica with developed pore structure greatly improves the light transmittance, and provides a trace of moisture and oxygen channels to facilitate the activation of Ag-NPs, significantly increases the antimicrobial efficiency of the coatings. PDA helps Ag-NPs to be uniformly dispersed and anchored on the surface of the silica, which significantly enhances the antibacterial performance and durability. In addition, the introduction of PDA reduces the surface roughness of the coating, thus reducing light scattering and attenuating the negative effect of Ag-NPs on light propagation. Under the optimal conditions, the antibacterial rate of GSPA-0.1–10 exceeds 99.9999 % (E. coli and S. aureus antimicrobial rate > 99.9999 % at 40 min and 3 h, respectively), and the light transmittance was maintained above 96 %. This work demonstrates a synergistic interaction between porous silica and PDA, which will provide a new approach for the functionalization of porous antireflective coatings.