Fluorescence performance and fractal feature of NA-grafted bimodal mesopores silica by Fe3+ modification

The Fe 3+ -modified 1, 8-naphthalic anhydride (Fe-NA) was prepared, and thereafter successfully grafted on the mesoporous surface of bimodal mesopores material (BMMs) by post-synthesis method. The influence of various parameters, including amount of Fe 3+ ion, various solvents, different concentrations and loadings of FC-NA on the fluorescence behavior of resultant hybrid materials (FC-NA grafted BMMs) was investigated, and then its fluorescence properties were compared to the parent FC-NA. Meanwhile, their structural properties and photoluminescence performances were investigated using various characterizations XRD , TEM , SEM, SAXS , FT-IR, TGA, ICP-OES, elemental analysis , N 2 adsorption-desorption isotherms, and fluorescence measurement. The results showed that the mesoporous structural integrity was remained intact after introduction of FC-NA in the mesoporous channels of APTES-BMMs. Particularly, SAXS patterns revealed the mass fractal dimension of the hybrid FC-NA@BMMs were gradually increased with increasing loaded amount of FC-NA, and resulted in the uneven distribution and self-similarity fractal features. The fluorescence profiles exhibited the occurrence of red-shifts and then blue-shifts of characteristic peak with increasing grafted FC-NA amount. These shifts demonstrated a highly aggregation on the amine-modified mesoporous surface of APTES-BMMs when the obtained mass ratio of FC-NA/AP-BMMs was lower than 0.2, whereas a uniform monodispersion distribution was observed when the mass ratio got higher than 0.2. The obtained functionalized mesoporous materials with enhanced fluorescence intensity have a potential application in drug sustained/controlled delivery systems.