Grafting, from silicon surfaces poly

During the last 5 years, there have been several reports of multiblock copolymer brushes by the grafting-from method. The most common substrates are gold and silicon oxide layers but there have been reports of diblock brush formation on clay surfaces [37] and silicon-hydride surfaces [38]. Most of the newer reports have utilized ATRP [34,38-43] but there have been a couple of reports that utilized anionic polymerization [44, 45]. Zhao and co-workers [21,22] have used a combination of ATRP and nitroxide-mediated polymerization to prepare mixed poly(methyl methacrylate) (PMMA)Zpolystyrene (PS) brushes from a difunctional initiator. These Y-shaped brushes could be considered block copolymers that are surface immobilized at the block junction. 

Mclnnes SJ, Irani Y, Williams KA, Voelcker NH (2012) Controlled drug delivery from composites of nanostructured porous silicon and poly(L-lactide). Nanomedicine (Lond) 7 995 Minko S (2008) Grafting on solid surfaces grafting to and grafting Irom methods. In Stamm M (ed) Polymer surfaces and interfaces. Springer, Berlin/Heidelberg, p 215 Mishra JK, Bhunia S, Baneijee S, Baneqi P (2008) Photoluminescence studies on porous silicon/ polymer heterostructure. JLumin 128 1169... 

Figure 58 A binary polymer brush layer on a silicon wafer was prepared from rubbery poly(methyl acrylate) (PMA) and glassy poly (styrene-co-2,3,4,5,6-pentafluorostyrene) (PSF) using the grafting from approach. A series of force-distance curves were collected before and after the experiments to confirm the deformation was elastic, (a) The experimental loading curve (circles), fitting with the trilayered model (solid line, almost completely buried by experimental data points) and Hertzian model (dashed line), (b) Experimental depth distribution of the elastic modulus for the polymer brush layer (circles) and the best fitting with the trilayered model (solid line) showing slight increase in the elastic modulus near the surface and sharp increase in proximity to a stiff substrate. Reprinted with permission from Kovalev, A. Shulha, H. Lemieux, M. et al. J. Mater. Res. 2004,19,716. Copyright 2005 Materials Research Society.

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