Structural and dynamic properties of confined ethane in AlPO4-5 model microporous aluminophosphate: Does the predicted quasi-(1D) phase transition exist?

Sorbed ethane in AlPO4-5 microporous aluminophosphate (MAP) is an interesting confined phase – host material system for quasi-(1D) phase transition investigation. Indeed, calculated C2H6 sorption isotherm in AlPO4-5 MAP, by molecular dynamics simulation (MDS), exhibits a nice isotherm sub-step interpreted as the signature of a confined phase transition [1]. The motivation of our neutron scattering study, which concerns the analysis of both the dynamic and structural properties of ethane confined phases in AlPO4-5, was firstly to validate or not the MDS results and secondly to precise the quasi-(1D) phase transition nature if it exists. Unfortunately, in the investigated temperature range [140–170 K] we do not observe any phase transition. Nevertheless, we determine the ethane confined solid structure observed in the full AlPO4-5 loading regime.