Dendrimers and hyperbranched polyesters as structure-directing agents in the formation of nanoporous silica

Anionic dendritic macromolecules (hyperbranched polyesters and polyamidoamine (PAMAM) dendrimers) and amine-functionalized PAMAM dendrimers have been used as structure-directing agents in the synthesis of nanoporous silica structures. When utilizing carboxylates as structure-directing agents the incorporation of the negatively charged species into a SiO 2 framework was achieved via a sol-gel synthesis route using a quaternized aminosilane as co-structure-directing agent to yield silica materials of various morphologies and high surface areas. Amine dendrimers as porogens gave materials with high surface areas, revealing increasing pore sizes corresponding to the increasing size of the porogen. The resulting materials have been characterized by X-ray diffraction (XRD), N-2 adsorption/desorption (BET), scanning electron microscopy (SEM), infrared spectroscopy (IR), and thermogravimetric analysis (TGA).