Enhanced Aging Stability of Ordered Mesoporous Silica Materials Synthesized via True Liquid Crystal Templating—A Small-Angle X-Ray Scattering Study

The long-term structural stability of ordered mesoporous silica (OMS) materials-specifically the durability of their pore architecture and pore lattice over time-is critical for their performance in catalysis, separation, drug carrier and nanoconfinement applications. SBA-15-type silica materials are synthesized via two different routes, namely the conventional "liquid crystal templating" (LCT) and the much less common "true liquid crystal templating" (TLCT) of micellar structures formed by the amphiphilic block copolymer Pluronic P123 in water. Here, we report that SBA-15 materials age very differently depending on the synthesis route: Under ambient conditions, OMS materials obtained via the LCT route undergo significant structural changes over time, especially in microporous regions, while SBA-15 materials obtained via the TLCT route show less or even no structural changes even after a year of storage. We attribute this enhanced aging stability of TLCT materials to their narrow mesopore size distribution and their much lower degree of microporosity.