Facile preparation of hierarchical mesoporous silica microspheres with tunable porous structure and particle sizes

This work reports that, by supplementing classical ternary template system (TEOS/P123/HCl(aq.)) with poly (vinyl alcohol) (PVA) as additive, hierarchical mesoporous silica (HMS) microspheres can be prepared with tunable particle sizes and porous structures based on the partitioned cooperative self-assembly (PCSA) process. The particle sizes and hierarchical mesoporous (HM) structures of HMS microspheres are found to dependent on the experimental parameters, such as PVA dosages, synthesis/hydrothermal treatment temperatures and partitioning conditions, etc. The BET surface area, pore volume and particle size of typical HMS microsphere sample of [email protected] reach 792 m2g-1, 1.74 cm3g-1 and 3.51 μm, respectively. The 1st and 2nd mode mesopore sizes are 10.5 nm and 20.5 nm, respectively. Large synthesis domains for HMS microspheres defined by different synthesis parameters were also obtained, enabling their easy and controllable preparation. The scaled-up preparation of HMS microspheres up to five times was also demonstrated with comparable particle morphology and sizes. PVA was newly found to play multiple roles in the preparation of HMS microspheres in (1) improving the dispersibility and spherical morphology, (2) shaping the HM structures and (3) broadening the synthesis domain. The facile and controllable HMS microspheres might further promote their application in different areas.