A facile fabrication of robust thiol-ene/hierarchically mesoporous silica nanoparticles hybrid superhydrophilic coating films under UV radiation

We report a facile approach to designing the robust organic-inorganic hybrid superhydrophilic coating films under UV radiation. It is based on the utilization of ene-terminated hydrophilic oligomer (ETHO) and hierarchically mesoporous silica nanoparticles (HMSNs). ETHO was firstly synthesized with DL-dithiothreitol and excess of poly(ethylene glycol) dimethacrylate at room temperature via thiol-ene reaction, and then by spraying the methanol solution containing ETHO, HMSNs, trimethylolpropane triacrylate as crosslinking agent, and Darocur 1173 as photoinitiator on substrate, the thiol-ene/HMSNs hybrid superhydrophilic coating films were fabricated under the exposure of UV light. The structure of ETHO was confirmed by FT-IR, H-1 NMR and C-13 NMR, its molecular weight was 7600 measured by GPC. The wetting behavior of the coating films was found to be largely determined by the mass ratio of HMSNs to ETHO. With the mass ratio at 0.75, the hybrid coating films could achieve superhydrophilic state within 0.24s, and SEM revealed the existence of double micro-nano structure on the surface, which was significant for the improvement of superhydrophilicity. Importantly, the superhydrophilicity of the coating film could be steadily maintained under the conditions of acid solution, boiling water and abrasion. Additionally, the coating films also exhibited excellent adhesion, flexibility and impact strength. (C) 2016 Elsevier B.V. All rights reserved.