One-pot and rapid synthesis of uniformed silica spheres via mediation of linear poly(ethyleneimine)s and dyes

Fabrication of monodisperse silica spheres with bright emission features is still valuable in challenging since the spheres are widely applicable in the fields of catalysis, imaging material, bio-encapsulation, drug delivery, coatings. cosmetic, energy storage, and so on. In this paper, we demonstrated a new one-pot approach to uniformed silica spheres via mediation of linear poly(ethyleneimine)s (PEIs) and acidic dyes. PEIs with different architectures possessing only secondary amine in backbone were used as mediators for silica deposition from hydrolytic condensation of tetramethoxysilane (TMOS). Under the optimized medium composition of methanol/water with 70/30 in volume, the PEIs facilely promoted the hydrolytic condensation of TMOS to give rapidly and exclusively uniformed silica spheres. In this process, acidic dyes such as tetrakis(4-sulfonylphenyl)porphyrin (TSPP), tetrakis(4-carboxylphenyl)porphyrin (TCPP) can be incorporated with basic PEIs and play important role to produce relatively larger uniformed silica spheres entrapping the dyes inside. The diameters of the uniformed silica spheres ranged from 50 to 700 nm depending upon polymer architectures. From time-course investigation, it is confirmed that the formation of the silica spheres has three stages: 1) early formation of widely distributed smaller spheres; 2) growth to uniformed intermediate silica spheres and 3) further growth into larger spheres with narrow distribution.