Topographical Functionalization of Ordered Mesoporous Silica

Fabrication of pore window in ordered mesoporous silica by spatial control of functional groups

“…One gram of as-synthesized MCM41 crystals was suspended in 0.1 M NaF solution (100ml) and stirred at 80 o C for 2 h to fluorinate external surface [22][23]. The reaction product was washed with deionized water, dried under an ambient atmosphere, and finally dehydrated at 120 o C for 6 h under N 2 environment.…”

“…In general, as-synthesized rod-shaped crystals expose only the silanol group of external surface because the silanol group of internal surface are tightly covered by packed templates. Simple fluorination of the as-synthesized crystals can lead to selective deactivation of the silanol groups of external surface [21][22][23]. Both the fluorinated external surface and most of the template-packed internal surface could hardly participate in subsequent grafting reaction.…”

“…Both the fluorinated external surface and most of the template-packed internal surface could hardly participate in subsequent grafting reaction. And subsequent grafting would result in localized attachment of organic groups only on pore entrance surface because the templates packed in the pores could be removed gradually from pore entrance to pore inside in a controlled rate [23]. Thus, the organic group selectively grafted on pore entrance surface act as a functional pore window.…”