High temperature behavior of periodic mesoporous ethanesilica glasses prepared from a bridged silsesquioxane and a non-ionic triblock copolymer

Periodic mesoporous organosilicas (PMOs) with 2D-hexagonal structure have been prepared by the sol–gel route in acidic conditions from a bissilylated reactive as a silica-modified source, namely 1,2-bis(triethoxysilyl)ethane (BTEE), and Pluronic® P123 non-ionic surfactant as a templating agent. Pyrolysis of the PMO material was performed under inert atmosphere up to 1000 °C in order to assess the possibility to transform the hybrid network into a porous SiOC glass network. The pyrolysis process has been mainly followed by 29Si and 13C solid state NMR. Thermal degradation of the pore network was followed by XRD and TEM and measured by N2 adsorption–desorption experiments. This study shows that despite the Si–C bonds cleavage occurring after 600 °C causes a phase separation into silica and free carbon, an ordered structure is retained up to 1000 °C with a remaining specific surface area.