Multiscale characterization of hierarchically organized porous hybrid materials

Abstract

In this work, monolithic hybrid materials exhibiting both meso- and macropores of controlled size have been prepared using the hydrolysis–condensation of modified silicon alkoxide in the presence of a surfactant. These materials have been thoroughly characterized using gas sorption, mercury intrusion porosimetry, small angle X-ray scattering and electronic microscopies both in scanning and transmission modes. Using these hierarchically porous samples, it has been possible to demonstrate for the very first time that the thermoporosimetry (TPM) technique, based on the measurement of transitions of confined liquids, is indeed valid over a very wide pore size range (from few nm up to several hundred nm) to characterize the porosity in solids. This first experimental evidence is a major breakthrough because it offers a unique technique covering the whole range from mesopores to macropores, filling the known gap from standard techniques. This unique combination of smart design of hierarchically porous materials and advanced calorimetric characterization of porous solids has also brought the first true calibration data for TPM on such a large size scale.