Visible Light Induced Interfacial Photo-Cross-Linking for Fabrication of Polymer Capsules Using Photoreactive Polymers with Substituted Cinnamates

Abstract

Capsule particles are widely used for various industrial applications. The interfacial photo-cross-linking of spherical polymer particles is a facile and safe approach for preparing capsule polymer particles. However, only ultraviolet light (e.g., λ = 265 nm) is used for the interfacial photo-cross-linking because the cinnamate group has been used as a ultraviolet light reactive group. In this study, we synthesize derivatives of 2-cinnamoylethyl methacrylate (CEMA) by introducing different substituents (o-nitro, m-nitro, p-nitro, and p-dimethylamino groups) to regulate the absorption wavelength of the photoreactive monomers. Using the photoreactive polymers comprising p-nitro-substituted CEMA, the interfacial photo-cross-linking reaction proceeds with λ = 365 nm LED light. Furthermore, interfacial photo-cross-linking proceeds with photoreactive polymers comprising p-dimethylamino-substituted CEMA with λ = 465 nm LED light as a visible light source. Moreover, the prepared hollow polymer particles with p-dimethylamino-substituted CEMA show the fluorescence property. Finally, we demonstrated wavelength-controlled selective interfacial photo-cross-linking of a polymer particle mixture comprising different photoreactive groups. Moreover, we successfully performed the interfacial photo-crosslinking of polymer particles with visible light.