Exploring Confined Media in Hybrid Mesoporous Silicas via Thermoporosimetry †

Abstract

We present a new perspective on thermoporosimetry (TPM), a technique traditionally used for pore size analysis, by demonstrating its potential as a tool for probing molecular interactions within hybrid mesoporous silica. Although TPM has been known for over half a century and offers advantages over conventional methods such as gas adsorption and mercury intrusion, its wider adoption has been limited by the need for precise calibration. In this work, we established empirical correlations between the melting point depression (∆T ) of four probe solvents and pore radius, using a reference series of non-hybrid silica materials with varying pore sizes. Based on this calibration, we synthesized a series of hybrid mesoporous silicas functionalized with phenyl and methyl groups via co-condensation, combined with spray-drying. We then applied TPM to compare the confinement behavior and pore structure of these hybrid materials with their non-hybrid counterparts. Our results highlight the sensitivity of TPM to interfacial chemistry, offering new opportunities for the characterization of hybrid materials beyond conventional porosimetry.