Low-temperature solution processible, solventless and transparent silica nanopar- ticle-dispersed epoxy hybrid materials

Low-temperature solution processible and solventless silica-epoxy hybrid materials composed of organically modified silica nanoparticles and epoxy monomers were successfully fabricated through simple sol-gel process and solvent evaporation. These silica-epoxy hybrid materials exhibited the homogeneous dispersion without any phase separation, aggregation, and gelation in the solventless environment due to the good surface modification of various organosilanes upon silica nanoparticles. The homogeneous dispersion between silica nanoparticles and epoxy monomers was confirmed by TEM. These homogeneously dispersed silica-epoxy hybrid materials can be formed into the films through the simple low-temperature solution coating and thermal-curing process for 30 min at 150 oC. The silica-epoxy hybrid materials showed high transmittance of above 90% in the visible wavelength regions regardless of the embedded content of silica nanoparticles. In particular, these solventless silicaepoxy hybrid materials exhibited the film formation ability with thick film thickness of several hundred μm without any cracks and the incorporated silica nanoparticles in hybrid films were homogeneously dispersed without any aggregation. In addition, these hybrid materials enhanced properties in mechanical hardness, adhesion, and thermal stability in proportion to the embedded content of silica nanoparticles and the hybrid films showed the good surface roughness of below 1 nm.