While the grafting of well-defined polymer brushes has become a common approach for the functionalization of flat solid surfaces as well as surfaces of nanoparticles and macropores (pores of diameter above 50 nm), much less attention has been directed towards a similar functionalization of surfaces of mesopores (pores of diameter 2 - 50 nm). Mesoporous materials constitute a very interesting class of solid supports, because they commonly exhibit high surface areas (100-1000 m2/g), and may exhibit mesopores of very uniform and readily adjustable size and well-defined geometry (for instance spherical or cylindrical). The mesopores may also feature quite uniform entrances, whose size can be controlled. Well-defined mesoporous solids can be composed of particles with periodic arrays of pores or with single voids accessible through porous walls. The above structural features make mesoporous materials an attractive platform for functionalization with polymer brushes. Recent work demonstrated that atom transfer radical polymerization (ATRP) is a robust platform for grafting from surfaces of mesopores. If the mesopores are sufficiently large (above ~10 nm) and the surface is suitably functionalized with initiator groups, normal ATRP renders layers of controlled thickness composed of polymer chains of low polydispersity (~1.05-1.1). Surface-initiated ATRP with activators regenerated by electron transfer (ARGET) can be readily employed, allowing one to functionalize the surfaces of mesoporous particles with polymer brushes of quite low polydispersity (~1.2-1.3) without using air-tight glassware and vacuum lines.

Polymer brushes grafted on high-surface-area periodic mesoporous silicas and related nanoparticles

248th National Meeting (2014)

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