IR Micro-imaging of mesoporous silicon as a model system for the investigation of hysteresis phenomena

Ensembles of molecules confined to mesopore spaces reveal features which may notably deviate from their behavior both in the bulk phase and under dominating host-guest interaction. A previous detailed investigation of molecular dynamics in Vycor porous glass with a pore diameter of 6 nm using pulsed field gradient nuclear magnetic resonance (PFG NMR) indicated that under identical external conditions (temperature, pressure), different “histories” of sample preparation may give rise to dramatic differences in their microdynamics [1–3]. One approach to rationalize the occurrence of historydependent states in mesoporous host-guest systems is the occurrence of a geometric disorder-induced rugged landscape in the free energy. To get deeper insight into this phenomenon, novel options provided by the development of IR micro-imaging [4] have been used in the present work.