Synthesis of Organic Core-shell Nanoparticles

In this study, core-shell organic nanoparticles were synthesized and their photophysical properties characterized. E,E-1,4-Bis[4'-(N,N-di-n-butylamino)styryl]-2,5-dimethoxybenzene [1] was synthesized and used to produce fluorescent nanoparticles.  Compound 1 exhibits strong fluorescence in its solid state and would be beneficial to be used in bioimaging applications, once core-shell particles have been synthesized and functionalized.  Octadecyl triethoxysiliane was used to encapsulate the dye nanoparticles as they formed, producing the resulting core-shell particles.  The process consists of adding a solution of compound 1 and octadecyl triethoxysilane in tetrahydrofuran to a nonsolvent while under sonication. The formation of the silicon dioxide shell was initiated using ammonium hydroxide.  Uncoated nanoparticles were firmed by the same method in the absence of the alkylsilane. Particle size and distribution were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM).  The polydispersity of the dye nanoparticles obtained with DLS was six percent and the TEM image portrayed small particles, although agglomeration has occurred due to the drying of the solvent on the carbon disc.  The silica encapsulated particles showed a higher poly dispersity than that of the bare particles at fifteen percent. TEM images showed a very small portion of single encapsulated particles.  This project is currently unfinished and encapsulation of the dye using the octadecyl triethoxysilane will continue to be altered with the intentions of producing core-shell particles with controllable size and low polydispersity.