An electron beam irradiation-assisted coating method for the regulation of hydrophilicity and hydrophobicity†

Developing a stable, reliable, and industrially compatible method to control hydrophobicity is crucial for separation, transportation, and the generation of special surfaces. An e-HMS-PDMS silica gel nanoparticle coating was prepared using a two-step electron beam irradiation (EBI) process, consisting of (i) grafting of two organic groups onto thiol-functionalized hollow mesoporous silica (HMS-SH) with 10 MeV EBI and (ii) curing of polydimethylsiloxane (PDMS) onto silicone rubber using the HMS hybrid materials prepared in step i as an additive with 200 keV EBI. The tuneable grafting of functional groups and the surface properties of the silica, which was embedded in the PDMS layer, allowed us to precisely control the hydrophilicity of the PDMS layer by means of altering the grafting gradient of the silica and the loading ratio of the monomers. A diverse range of vinyl-structured monomers can be used in this method, and the selection of suitable monomers is vital in determining the physical properties of the coating layer. The hydrophilicity of the coating can be linearly controlled within a specific range (50° to 155°) by using suitable monomers, allowing for the design of surfaces with specific hydrophilic and hydrophobic requirements.

Keywords: Electron beam irradiation; Nanoparticle composite coating; Hydrophilicity/hydrophobicity; Thiol-ene click reaction.