(752b) Hierarchically Porous Microparticles VIA Spray Drying

The versatility of mesoporous silica with tailored pore size and functionality renders it ideal for a wide range of applications such as bio-adsorption and as catalyst substrates. A rapid synthesis method combining evaporation induced self-assembly and surfactant templating via spray-drying can overcome drawbacks associated with traditional synthesis routes, namely long processing time, non-scalable batch operations, and that most powders are sub-micron polydisperse particles. A micro-fluidic jet spray-dryer, developed at Monash University, was used to produce monodisperse microparticles with mesoporous characteristics. We demonstrated that hierarchical structures could be generated through the addition of co-templates in the precursors. Microparticles produced with pluronic block copolymer (F127) with the addition of Eudragit RS 30D ®, a polymer-colloidal dispersion of ~ 120 nm nanoparticles as a co-template, produced microparticles with very open, porous structure with macropores of the ~ 120 nm, along with ~9 nm mesopores. These particles exhibited highly ordered hexagonal mesostructures in addition to the macropores created by the removal of the polymer, with surface areas up to 460 m²/g and pore volumes up to 0.68 cm³/g. Through the variation in weight ratio of the co-templates and the silica different hierarchical structures can be obtained. These macro-meso-structures can be used for a range of applications such as bioseparation and bioadsorption in dynamic systems and for immobilisation of bio-catalysts.