Table 1. Comparison of physicochemical properties of various PMO materials.
| PMO | B.E.T. surface area a (m2 g–1) | Mesopore volume b (cm3 g–1) | Pore size c (nm) | Silanol surface density d , αOH (mmol g–1) | OH e per nm2 |
| T100 | 709 | 1.12 | 9.7 ± 0.5 | 2.1 | 1.8 |
| T75-B25 | 668 | 0.99 | 7.6 ± 0.3 | 1.7 | 1.5 |
| T50-B50 | 694 | 1.00 | 7.5 ± 0.7 | 1.7 | 1.5 |
| T25-B75 | 708 | 1.08 | 7.1 ± 0.7 | 2.1 | 1.8 |
| B100 | 721 | 1.08 | 7.7 ± 0.8 | 1.5 | 1.3 |
| B75-BP25 | 719 | 1.01 | 6.3 ± 0.3 | 2.1 | 1.8 |
| BP100 | 728 | 1.18 | 5.0 ± 3.6 | 1.9 | 1.6 |
aCalculated using the Brunauer–Emmett–Teller (B.E.T.) method. The generally accepted measurement error is ±10%.41 The calculations assume an area for adsorbed N2 of 0.135 nm2 per molecule, which is the value appropriate for perpendicular adsorption on oxide surfaces.32 Since N2 adsorbs parallel to the surface on organic materials, occupying a larger area (0.162 nm2), the actual surface areas of the organosilicas may be somewhat higher, but the fractions of parallel vs. perpendicularly adsorbed N2 are not known. Finally, B.E.T. surface areas normalized by mass do not reflect differences in skeletal densities for silicas with different organic fractions.
bMeasured at P/P0 = 0.99, except for BP100, for which P/P0 = 0.95 was used (see Fig. S6).
cCalculated using the Barrett–Joyner–Halenda (B.J.H.) method, using the adsorption branch of the isotherm, and reported as the average pore size and standard deviation.
dThe measurement error associated with these values is estimated to be ±0.1 mmol g–1.
eThe error generated due to the experimental uncertainty in the surface area measurements is ±0.3 nm–2.