A 3D-TEM study of the shape of mesopores in SBA-15 and modified SBA-15 materialsElectronic supplementary information (ESI) available: Fig. S1: schematic view of the MCM-41 formation mechanism. Movie S2: Aligned TEM tilt series of the SBA-15 particle from Fig. 1 (sample with the lower TEOS to template ratio). Movie S3: Aligned TEM tilt series of the SBA-15 particle from Fig. 3 (sample with the higher TEOS to template ratio). See http://www.rsc.org/suppdata/cc/b2/b204943k/