Silica polymer grafting

Preparation and Stability of Polymer-Grafted Silica Dispersions... 

Structure EANPS = electrostatic agglomerated nonporous substrate, EAWPS = electrostatic agglomerated wide-pore substrate, PGPS = polymer grafted porous substrate, SMPSS = silane modified porous silica substrate, CMS = chemically modified substrate, APCS = adsorbed polymer coated substrate. 

Tsubokawa et al. (12-14) have introduced radical sources of azo or peroxy groups by another methods, and successively conducted the radical polymerization of vinyl compounds, such as styrene or methyl methacrylate, to give polymer-grafted particles see Reaction (3). The grafting by the radical polymerization of methyl methacrylate, initiated from a peroxy group introduced on silica, takes place at relatively high efficiency, compared with those from azo group-introduced particles. 

Plasma Polymerization. Plasma-induced polymerization (24) of vinyl monomer from inorganic particles is also employed for polymer grafting. The conventional reactors for liquid-phase polymerization of vinyl compounds after generation of plasma on inorganic particles or powders have been recently invented by Ikeda et al. (25). Haraguchi et al. (26) have also prepared polymer-modified silica by plasma-induced polymerization of glycidyl methaciylate. 

Polymer-grafted silica (SiO2) particles represent one of the most popular colloidal systems with tunable interactions. Ilie chains of choice were mainly polystyrene, poly(dimethyl siloxane), poly(butyl methacrylate), and n-octadecyl or stearyl alcohol. Chain grafting provided the means to tailor the colloidal particle behavior from hard to soft, as well as introduce attractions in a controlled way by varying the temperature or adding non-absorbing polymer depletant [44,95-112]. 

FIGURE 6.8 (a) Schematic illustration of the procedure for the synthesis of polymeric capsules based on surface-initiated RAFT polymerization using silica nanoparticles as templates, (b) TEM image of polymer grafted silica nanoparticles, (c) SEM and (d) TEM images of the synthesized polymeric capsules. Source Huang et al. [15]. Reproduced with permission of American Chemical Society. 

---