SPB nanoreactors

Lu et al. (2007b) have synthesized silver (Ag) NPs in an SPB nanoreactor in a different way. The PS core was synthesized and HMEM applied as photoinitiator as described by previous Hterature (Guo et al., 1999 Marra et al., 2003 Mei et al., 2003). In the final step, silver acrylate was used as a functional monomer to grow SPB on the PS core. Meanwhile, Ag NPs were generated from Ag" ", which were confined as counterions in the presence of UV fight (Fig. 4.20). 

Figure 4.19 TEM image showing the size of Pt NPs generated by SPB nanoreactor (Mei et al., 2005).

Ni NPs have been prepared in SPB nanoreactors by our group (Zhu et al., 2011). The size ofNPs can be tuned by changing the temperature during preparation. Ni replaced the counterions in SPB and then reduced to form Ni NPs in the presence of NaBH4. TEM images ofNi NPs are shown in Fig. 4.24. 

NPs were prepared in PAA SPB nanoreactor through the conventional coprecipitation method (Zhu et al., 2012). To lock the prepared NPs in SPB, small amounts of JV,J /-methylenebisacrylamide (BIS) were always used as crosshnkers. TEM images of SPB with and without magnetic NPs are shown in Fig. 4.26. 

The distinctive features of spherical polyelectrolyte brushes (SPB) as ideal nanoreactors are discussed. SPB containing colloidal particles on which polyelectrolyte chains have been densely grafted offer a wide range of potential applications. They are ideally suited for the generation and immobilization of metal or metal oxide nanoparticles, which can be applied as smart catalysts in chemical industry. SPB can also be used for immobilization of proteins and enzymes. The response to external stimuli makes SPB unique in the field of nanoreactors. 

Ultrafine nanosized magnetic particles can be prepared in situ by using SPB as a nanoreactor (Zhu et al., 2012). Magnetic response is thus induced in SPB. The apphcations of Magnetic spherical poly electrolyte brushes (MSPB), in addition to separation and recycHng, include heat generation (Gelbrich et al., 2010). 

SPB have been apphed in numerous fields due to their different characteristics. In the following section, their vast appHcations as nanoreactors are discussed. 

Due to its nontoxicity, chemical stability and photocatalytic activity, ZnO has attracted great attention recently. Our group has synthesized well-defined ZnO NPs by using SPB as a nanoreactor. To increase the amount of ZnO, multigeneration cycles were employed (Fig. 4.27). 

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