Evaporation-Induced Coating and Self-Assembly of Ordered Mesoporous Carbon-Silica Composite Monoliths with Macroporous Architecture on Polyurethane Foams

A facile approach of solvent-evaporation-induced coating and self-assembly is demonstrated for the mass preparation of ordered mesoporous carbon-silica composite monoliths by using a polyether polyol-based polyurethane (PU) foam as a sacrificial scaffold. The preparation is carried out using resol as a carbon precursor, tetraethyl orthosilicate (TEOS) as a silica source and Pluronic F127 triblock copolymer as a template. The PU foam with its macrostructure provides a large, 3D, interconnecting interface for evaporation-induced coating of the phenolic resin-silica block-copolymer composites and self-assembly of the mesostructure, and endows the composite monoliths with a diversity of macroporous architectures. Small-angle X-ray scattering, X-ray diffraction and transmission electron microscopy results indicate that the obtained composite monoliths have an ordered mesostructure with 2D hexagonal symmetry (p6m) and good thermal stability. By simply changing the mass ratio of the resol to TEOS over a wide range (10-90%), a series of ordered, mesoporous composite foams with different compositions can be obtained. The composite monoliths with hierarchical macro/mesopores exhibit large pore volumes (0.3-0.8 cm(3) g(-1)), uniform pore sizes (4.2-9.0 nm), and surface areas (230-610 m(2) g(-1)). A formation process for the hierarchical porous composite monoliths on the struts of the PU foam through the evaporation-induced coating and self-assembly method is described in detail. This simple strategy performed on commercial PU foam is a good candidate for mass production of interface-assembly materials.