Exploring the Diffusion Properties of Pseudomorphic MCM-41 Materials by PFG NMR

1. Introduction Ordered mesoporous silicas such as micelle-templated silicas (MTS) feature unique textural properties in addition to their high surface area: narrow mesopore size distributions, controlled pore size and connectivity make them particularly suitable for chromatographic applications (size exclusion chromatography, HPLC and capillary gas chromatography). In these applications, the particle morphology has to be tailored at the micrometer scale and the preparation of mesoporous silicas in the form of discrete monodisperse spheres with tunable sizes has been possible using the concept of pseudomorphic transformation [1]. Considering the foreseen applications, mass transfer properties are of considerable importance for these materials. On this subject Pulsed Field Gradient (PFG) NMR has proved to be a successful tool to study the diffusion of various molecules in porous materials [2]. The aim of this work is to show that PFG can be used to characterize the diffusion properties of pseudomorphic samples of MCM-41 at different synthesis stages.