The mechanism of channel formation in the mesoporous molecular sieve MCM-41

We propose a model of channel growth in mesoporous molecular sieves based on new evidence from high-resolution transmission electron microscopy and X-ray diffraction. The silicate enters a silicate/surfactant aggregate through the surface perpendicular to its axis, but the surfactant enters along the axis. The pore–pore distance is initially larger near the surface of the particle. As the synthesis proceeds, silicate penetrates towards the centre of the particle and the pore–pore distance becomes uniform. At high temperatures and long reaction times, the maximum diameter of the surfactant rods depends only on the size of the template molecule.