(647g) Hierarchical Silica Particles by Dynamic Multicomponent Assembly

Wu, Z., Tulane University
Hu, Q., General Motors R&D Center
Pang, J., Tulane University
Lu, Y., Tulane University

Supramolecular-templated mesoporous materials have attracted much attention since their discovery in the early 1990s. These materials possess a few unique properties, such as controllable pore size, high surface area,high pore volume, and highly ordered structure, which make them potential candidates for various applications. In this work, we report an aerosol-assisted self-assembly of silica particles with tunable mesostructures at multi-length scale using hydrophobic Poly(prop ylene oxide) (PPO) and amphiphilic molecules as co-templates. During aerosol-assisted multi-scale self-assembly process, PPO molecules will enter the hydrophobic cores of surfactant micelles, co-assemble with the amphiphilic molecules and alter the packing parameters, which may change the mesostructures of obtained mesoporous silica. Increasing molecular weight of PPO increases the hydrophobic interactions among PPO moleculaes. When the molecular weight of PPO is relatively high, they prefer aggregation to form surfactant-stabilized PPO aggregates, which co-exist with surfactant lyotropic liquid crystal phase. Removal of surfactant and PPO molecules from such hierarchical silicate/surfactant/PPO nanocomposites creates silica particles with hierarchical structures. This design concept is of interest for the design and synthesis of other assembled materials with targeted hierarchical structures for various applications.