Dendrimer Template Directed Self-Assembly during Zeolite Formation

We describe the formation of a spherical complex driven by the incorporation of aluminosilicate in a dendrimer charged surface. By using a carboxyl-terminated dendrimer species as a macromolecular template for zeolite formation, we detected the formation of porous, stable, and nearly monodisperse spherical aggregates with an average radius of R ) 3500 Å. The presence of the charge in the surface of the dendrimer, acting as the main driving force, influences the crystallites aggregation as well as the long-range assembly conditions for the zeolite growth. The main finding of our results suggests a possible mechanism for nanoaggregates formation. The dendrimer carboxylate end groups, which are responsible of the long-range electrostatic interparticle interaction, create a diffuse layer of condensed Na+ ions in the neighborhood of the dendrimer surface which act as the effective structure-directing agent for the zeolite LTA formation. This study put novel insight into the investigation of alternative protocols for the assembly mechanism of porous materials.