Synthesis of acrylate-based UV/thermal dual-cure coatings for antifogging

A dual-cure hydrophilic acrylate polymer was synthesized via radical polymerization with acrylic acid (AA), isophorone diisocyanate (IPDI), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), hydroxyethyl acrylate (HEA), and 3-(trimethoxysilyl)propyl-2-methyl-2-methacrylate (MPS) as monomers, then used as prepolymer for antifog coating with tetraethylorthosilicate (TEOS) as a novel crosslinker. The prepolymer was mixed with crosslinking agent and photoinitiator to form coating formulas. The coating was characterized by nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR) spectroscopy, and contact angle measurements. The results indicated that the dosage of AMPS and TEOS had great influence on the antifog performance. With an increasing TEOS amount, the hardness, adhesion, water resistance, impact resistance, and thermal stability of the films were improved, at the expense of transparency; with increasing dosage of AMPS, the hydrophilicity of the film increased at the expense of water resistance. Optimum coating properties could be obtained when the amount of AMPS was 7% and that of TEOS was 5.5%. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) results showed that some SiO₂ microspheres were formed and microphase separation occurred between the macromolecular segments, yielding the excellent coating properties.