Nitroxide-Mediated Polymerizations from Silica Nanoparticle Surfaces:  “Graft from” Polymerization of Styrene Using a Triethoxysilyl-Terminated Alkoxyamine Initiator

Abstract

Nitroxide-mediated stable free radical polymerization of styrene was performed from 13 nm diameter silica nanoparticles in two steps. First, an alkoxyamine, based on N-tert-butyl-N-(1diethylphosphono-2,2-dimethylpropyl) nitroxide (DEPN) carrying a terminal triethoxysilyl functional group was synthesized and covalently attached onto silica. Polystyrene chains with controlled molecular weights and narrow polydispersities were then grown from the alkoxyamine-functionalized nanoparticles surface. The grafting of both the initiator and the polystyrene was qualitatively evidenced by FTIR spectroscopy and solid-state NMR and quantified by thermogravimetric and elemental analysis. More than 40% of the surface bound alkoxyamine initiator participated in the growth reaction. Polymer graft densities of around 110 chains per particle were obtained by this technique.

Preparation of polyamide 6/silica nanocomposites from silica surface initiated ring-opening anionic polymerization

“…An effective approach to overcome these barriers is to functionalize the silica surface with polymers that are identical or structurally similar to the matrix polymers. Among the widely pursued functionalization strategies is the 'grafting from' method [8,9], in which monomers or initiators are first attached to the silica surface to serve as starting points for propagation. For example, the silicabound azo moieties have been used in the conventional radical polymerization to graft vinyl polymers onto silica surfaces [10,11].…”

Surface Modification of Spherical Particles with Bioactive Glycopolymers

“…39 The 2-step synthesis of the protected glycomonomer tetAcGlc was carried out according to literature: after 40 the final product could be achieved by a ring opening reaction with hydroxyethyl methacrylate. 41 The synthesis of methacrylic inimer 2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM) was carried out according to the method described earlier.…”

“…The latter include reversible addition-fragmentation chain transfer polymerization (RAFT), [21][22][23][24][25][26][27][28][29] atom transfer radical polymerization (ATRP) [30][31][32][33][34][35] and nitroxide mediated polymerization (NMP). [36][37][38][39][40] Applying these techniques, a plethora of linear glycopolymers bearing various carbohydrate moieties were synthesized and analyzed. Linear glycohomopolymers show an interesting behavior in matters of bioactivity and biorecognition towards proteins, but their use for applications regarding biosensors or drug delivery is often limited.…”

“…In this approach hyperbranched polymers first grow in solution, then add to the PDVB vinyl groups, and grow further in a grafting onto -grafting from fashion. Given that surface grafted and free polymers in solution have comparable molecular weights and polydispersity indices, [38][39][40][41][42] the characterization of the unbound glycopolymers is a facile way to determine the properties of the grafted polymers. The experimental results are summarized in Table 2.…”

Graft Polymerization of Dimethylacrylamide onto Polysilsesquioxane Containing Mercapto Groups

“…2,3 Furthermore, the expectation is supported by the recent studies on the introduction of polymeric components onto the related polysiloxane compounds such as silica, zeolite, and clay to modify or improve the properties. [4][5][6][7][8] For the effective grafting, the living polymerization techniques via radical species such as atom transfer radical polymerization process [9][10][11][12] and the use of photoiniferter 13 are appropriately utilized in the recent investigations. These living polymerization techniques contribute to minimize the formation of free chains, control the chain length, and the easy formation of block copolymer chains.…”