Role of phosphate-modified mesoporous silica nanoparticles for altering biomimetic metal-induced aggregation process of pluronic F127 block copolymer

Phosphate-modified mesoporous silica nanoparticle (PMSN) with large pores over 10 nm is very effective in disrupting biomimetic aggregates of Pluronic® F127 PEO-PPO-PEO block copolymer induced by Mn²⁺. Mesoporous silica nanoparticles were prepared using cetyltrimethyl ammonium bromide (CTAB) and tetramethyl orthosilicate (TMOS) in basic conditions. Mesopores were expanded up to 15 nm using 1,3,5-trimethylbenzene (TMB) as a pore expander and phosphate groups were attached on the surface of mesoporous silica nanoparticles using 3-(trihydroxysilyl)propyl methylphosphonate (THPMP). F127 block copolymers formed aggregates in Mn²⁺-containing methanol solution and the aggregation process was abruptly reduced by adding small amount of PMSNs, which are attributed to negatively-charged phosphate groups on PMSN surface and high mesoporosity of PMSNs. TEM images clearly showed PMSNs adsorb F127 block copolymers as well as Mn²⁺.