Mesoporous silicas are high surface area materials that are promising candidates as supports for heterogeneous catalysts. It is often found that the surface properties of the silica i.e. hydrophobicity, have a significant effect on the pathways that occur in reactions. Here, we examine the addition of methyl groups to the surface of mesoporous silica. The results show that the mesoporous structure is maintained after the addition of organic groups, and that a lattice contraction is observed with increasing modifier content.