A robust transparent encapsulation material: Silica nanoparticle-embedded epoxy hybrid nanocomposite

We report on the synthesis of a silica nanoparticle-embedded epoxy nanohybrid (SNP-EP nanocomposite), that can be used as a robust transparent encapsulation material for various applications. The SNP-EP nanocomposite is composed of a thermo-curable, bisphenol A-type epoxy polymer as a matrix and monodispersed silica nanoparticle (SNP) as a reinforcement, which can create tortuous diffusion path for moisture penetrants. SNP is synthesized via a base-catalyzed hydrolytic sol-gel condensation, and the surface of the SNP is modified with glycidyl and phenyl ligands to endure stable dispersion and chemical cross-linking with epoxy matrix. The SNP-EP nanocomposite exhibits significantly enhanced water vapor transmission rate of 1.52 g/m2 day and an optical transparency over 90% in the visible range with strong adhesion (5B). We introduce synthetic steps of the nanocomposite and discuss physical/chemical properties of the composite.