Improving structural analysis of disordered mesoporous materials using NMR cryoporometry

摘要

A microscopic, lattice-fluid model was employed to analyze freezing and melting behavior of fluids confined to linear pores of mesoporous silicon. The model predicts that mesoscalic disorder, inherent to this material, results in strong pore-blocking on freezing. On the other hand, it reveals that the existence of disorder leads to an interplay of three different mechanisms controlling the melting behavior. They are shown to be associated with metastable radial melting of pore narrowings, with axial melting of superheated solid, and with inverse pore-blocking due to the largest pores. On the basis of these findings, strategies for the improvement of structural analysis of mesoporous solids using cryoporometry techniques are discussed.