Fabrication of ionic liquid-functionalized silsesquioxane coating on transparent substrates via epoxide ring-opening reaction for antifouling applications

In this work, an epoxy-functional silsesquioxane (AEOS) was synthesized via the hydrolysis-condensation of 3-(glycidyl)propoxy trimethoxysilane and deposited onto glass substrates to form a silsesquioxane coating (Glass/AE). An imidazolium-based ionic liquid containing an amide group (IL-NH₂) was subsequently grafted onto the coating through ring-opening reactions, yielding an ionic liquid functionalized silsesquioxane coating (Glass/AE-IL-NH₂). The resulted coating exhibited an antibacterial rate exceeding 80% against E. coli and S. aureus , while achieving anti-adhesion removal efficiencies of 80% and 79% against Porphyridium and Dunaliella , respectively. The antifouling function results from the synergistic effect of the low surface energy of the silsesquioxane matrix and the bactericidal activity of the grafted ILs. In addition, the Glass/AE-IL-NH₂ coating demonstrated excellent water-lubrication properties and high optical transparency, making it a promising candidate for marine antifouling applications that require both optical clarity and long-term resistance to biofouling.