New Insights from Nonequilibrium Kinetics Studies on Highly Polar S-Methoxy-PC Infiltrated into Pores

Herein, the annealing of highly polar (S)-(-)-4-methoxymethyl-1,3-dioxolan-2-one (S-methoxy-PC) wit h i n alumina and silica porous membranes characterized by different pore diameters was studied by means of dielectric spectroscopy. We found a significant slowing down of the structural dynamics of confined S-methoxy-PC with annealing time below and, surprisingly, also above the glass transition temperatures of the interfacial layer, Tg,interfacial. Furthermore, unexpectedly, a change in the slope of temperature dependencies of the characteristic time scale of this process tau anneal , at Tg,interfacial for all confined samples, was reported . By modeling tau anneal(T), we noted that the observed enormous variation of tau anneal results from a decrease of the pore radius due to the vitrification of the interfacial molecules. This indicates that the enhanced dynamics of confined materials upon cooling is mainly controlled by the interfacial molecules.

Automated summary

In this study, the annealing of confined S-methoxy-PC within alumina and silica porous membranes was investigated using dielectric spectroscopy. It was found that the structural dynamics of confined S-methoxy-PC significantly slowed down below and above the glass transition temperature of the interfacial layer. Unexpectedly, a change in the temperature dependence of the characteristic time scale was observed at the glass transition temperature for all confined samples. Modeling results suggested that the decrease in pore radius caused by the vitrification of interfacial molecules contributed to the observed variation in the characteristic time scale.