Controlled/living polymerization techniques

Axel H. E. Muller obtained his PhD in 1977 from Johannes Gutenberg University in Mainz, Germany, for the work on the kinetics of anionic polymerization with G. V. Schulz. Since 1999, he has been professor and chair of macromolecular chemistry at the University of Bayreuth. In 2004, he received the lUPAC MACRO Distinguished Polymer Scientist Award and since 2011, he has been a Fellow of the Polymer Chemistry Division of the American Chemical Society. He is senior editor of the journal Polymer. His research interests focus on the design of well-defined polymer stmctures by controlled/living polymerization techniques and on self-organized nanostructures and hybrids obtained from them. He has coedited five books and published over 400 research papers. 

In this chapter, the synthetic strategies based on controlled/ living polymerization techniques that lead to well-defined... 

Fig. 7. Controlled or controlled/living polymerization techniques potentially applicable to synthesis of water-soluble or amphiphilic copolymers.

AM is difficult to polsrmerize by any of the controlled/living polymerization techniques. However, McCormick and co-workers have recently made significant progress in this area by reporting the CLRP, via RAFT, of AM in both aqueous and organic media (47,49,50). To achieve hving conditions, judicious choices must be made with respect to RAFT chain transfer agent (CTA) and polymerization conditions. 

While these living polymerization techniques do offer the ability to prepare block polyampholytes they are both synthetically demanding and somewhat limiting with respect to monomer choice for example. There are a handful of reports detailing the synthesis of block polyampholytes using controlled/living polymerization techniques discussed earlier (Fig. 47). For example, Gabaston and co-workers have described the TEMPO-mediated SFRP of block copolymers of sodium 4-styrenesulfonate IIZ with 4-(dimethylamino)methyl styrene 12Z (133),... 

The use of macromonomers in controlled living polymerization techniques, such as ionic or CRP, is at present the preferred synthesis strategy for the preparation of relatively well-defined graft copolymers. Macromonomers are oligomers fitted with polymerizable end-groups, mainly styrenic or (meth)acrylic, that can copolymerize with monomers to form comb-type graft copolymers with pendent preformed polymer chains. 

FIGURE 3.2 Polymer architectures via controlled/ living polymerization techniques. 

Research on the synthesis of polypeptide hybrid diblock copolymers began in the mid-1970s (Yamashita et al., 1975). Advances in polymer synthesis, culminating in the development of controlled/living polymerization techniques and click chemistry (Sumerlin and Vogt, 2010), in combination with the living ROP of NCAs, allowed for the preparation not only of simple diblock but also of a wide variety of multiblock Chimeras. In this section we will describe the materials synthesized according to the macroinitiators used for the ROP of the NCAs amino-and transition-metal complexes. 

Controlled/living polymerization techniques in combination with living ROP of NCAs can lead not only to linear but also to nonlinear chimeras. In this section we will describe the materials synthesized according to their structure star, comb, brush-block, and dendritic-like chimeras. 

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