Effective mesopore tuning using aromatic compounds in the aerosol-assisted system of aluminium organophosphonate spherical particles.

Spherical particles of ordered mesoporous aluminium organophosphonates (AOPs) were fabricated by spray-drying of precursor solutions containing Pluronic F127 (EO106PO70EO106) at low temperature. Expansion of the mesopores (10.5 nm) were investigated using the triblock copolymer by the addition of typical aromatic compounds such as 1,3,5-trimethylbenzene (TMB) and 1,3,5-triisopropylbenzene (TIPBz). 1,3,5-TIPBz was more useful than 1,3,5-TMB for obtaining spherical AOP particles with large mesopores (>20 nm) because 1,3,5-TIPBz with the boiling point (235 °C) much higher than the spray-drying temperature (~110 °C) was accommodated in the surfactant assemblies effectively. The boiling point of 1,3,5-TMB (165 °C) was not so high that it cannot stay completely in the surfactant assemblies during the spray-drying process, and thus smoothness of the surfaces was also deteriorated by evaporation of 1,3,5-TMB. Accordingly, the use of 1,3,5-TIPBz is effective for tuning uniform mesopores in the aerosol-assisted system of mesoporous AOP spherical particles with smooth surfaces.