Investigation of Low-Temperature Thermal Properties of Liquid Water and Benzene Confined within Silica-gel Nano-pores

Abstract

Thermal properties of water and benzene confined within silica-gel mesoporous materials MCM-41 and SBA-15 were investigated by adiabatic calorimetry. Confined water crystallized at low temperature while forming a boundary water layer of an amorphous state. The layer buffered the water content which is located in internal part of the pore from the effect of the pore wall, and kept it like bulk water. Confined benzene was affected by the presence of the pore wall. The configuration entropy S_conf of confined benzene in a liquid state decreased with decreasing a pores size. Crystallizations of both liquids were inhibited when they were confined within small pores of certain pore diameters, respectively. Both liquids confined within such small pores became stabilized at low temperature in different ways, respectively.