One-Step Production of Amine-Functionalized Hollow Mesoporous Silica Microspheres via Phase Separation Induced Cavity in Miniemulsion System for Opaque and Matting Coating

Compared to other well-developed synthetic methods, we developed a novel “phase separation inside monomer droplets” strategy in miniemulsion polymerization to fabricate hollow mesoporous silica microspheres (HMSMs) with an average diameters of ~ 500 nm. The flexibility of the proposed method was further demonstrated to fabricate amino groups modified HMSMs (HMSM-NH2) via co-condensation of TEOS and added 3-aminopropyltriethoxysilane (APTES) confined in oil phase. Waterborne polyurethane grafted HMSM-NH2 (HMSM-NH2-g-WPU) particle brushes were prepared by chain extention reactions between HMSM-NH2 and NCO groups terminated PU prepolymer during the self-emulsification process. HMSM-NH2-g-WPU coating provided opacity of 90% with only 4 wt % of HMSM-NH2 addition and exhibited a gloss of 3.1 (60o) with 5 wt % of HMSM-NH2 addition, respectively. The one-pot miniemulsion production of HMSM-NH2 combined with widely used industrial WPU production lines enables its excellent industrial scalability with promising app...