PH and thermo dual-sensitive copolymers with fluorescent properties grafted mesoporous silica SBA-15 via metal-free ATRP

Abstract

Well-defined pH and thermo dual-sensitive random copolymers poly(2-(diethylamino)ethyl methacrylate)–co-poly(N-isopropylacrylamide)–co-Eu complex with fluorescent properties grafted mesoporous silica SBA-15 (SBA-15-g-PDEAEMA-co-PNIPAM-co-Eu complex) was prepared by surface-initiated metal-free atom transfer radical polymerization (metal-free ATRP). The ATRP initiator 2-bromoisobutyryl bromide (BIBB) was immobilized on the SBA-15 surfaces followed by metal-free ATRP of 2-(diethylamino)ethyl methacrylate) (DEAEMA), N-isopropylacrylamide (NIPAM) and Eu complex. The hybrid material was characterized by fourier transform infrared spectroscope (FT-IR), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), thermal gravimetric analysis (TGA), N2 adsorption/desorption measurements, X-ray powder diffraction (XRD), Fluorescence spectrum and Nanoparticle Size-Zeta potential analyzer. The results showed that the SBA-15-g-PDEAEMA-co-PNIPAM-co-Eu complex hybrid material has been prepared successfully. The pore size, pore volume and specific surface area of SBA-15 decreased after grafting of the copolymers, but the ordered structure of SBA-15 pore still remained. The fluorescence testing suggested that the hybrid material had good fluorescence characteristics. The pH and temperature sensitivity analysis suggested that the hybrid material dispersion was good under low temperature and acid condition because the polymer chains stretched.