Telechelic Amphiphilic Polymers

Velichkova R. S., Christova D. C. Amphiphilic polymers from macromonomers and telechelics. In Progress in Polymer Science 1995 20(5) 819-887. 

Figure 15.4 Illustration of different subclasses of biocidal polymers (a) amphiphilic polycations, (b) telechelic biocidal polymers, and (c) hydrophilic...

Nonionic amphiphilic telechelic polymers consisting of polyethylene oxide with polyhedral oligosilsesquioxane, POSS, termini were prepared by Mather [3] and used as surfactants and thickening agents. The hydrophobicity of these amphiphilic telechelics, (III), was controlled by varying the molecular weight of the polyethylene oxide component. 

In recent years, there have been significant developments in the field of living carbocationic polymerization (LCCP) of vinyl monomers, such as isobutylene (IB), styrene and its derivatives, and vinyl ethers, leading to a wide variety of functional polymers (for recent reviews see Refs. 1-4). Due to the attractive properties of polyisobutylene (PIB) available only by carbocationic polymerization, coupling this hydrophobic, thermally, oxidatively, and hydrolytically stable polymer with a low Tg to a variety of other chain segments is expected to result in new useful products. For instance, methacrylate-telechelic PIB (MA-PIB-MA) obtained by LCCP and subsequent chain end derivatization has been successfully used to synthesize novel amphiphilic networks by radical copolymerization of MA-PIB-MA with a variety of monomers, such as N,N-dimethylacrylamide and 2-trimethylsilyloxyethyl methacrylate, a protected 2-hydroxyethyl methacrylate... 

FIGURE 2.1 Various possible architectures for amphiphilic copolymer (a) linear block copolymers with different numbers of A and B blocks, (b) cyclic block copolymers, (c) star block copolymers, (d) graft block copolymers, (e) block copolymers with dendritic or hyper-branched blocks, and (f) semitelechelic polymer (upper), telechelic polymer (middle), and asymmetrical telechelic polymer with different hydrophobic chain ends [9]. 

At this stage, we realize that we can study monofunctional polymers (/ = 1) and telechelic polymers (/ = 2) (and also their mixtures) from the unified point of view described above. Important examples of the monofunctional case are amphiphilic diblock... 

There are numerous reports in the literature describing the synthesis of low polydispersity PNIPAm (co)poly-mers via CRP methods. For example. Binder et al. [54] described the synthesis of telechelic PNIPAm using functional NMP initiators modified via azide-alkyne cycloadditions. Efficient block copolymerization of NIPAm with styrene was achieved via sequential polymerization initiated by a-hydrogen alkoxyamine [55]. A PNIPAm block was first prepared and then chain extended with styrene yielding amphiphilic diblock copolymers. Initial attempts to use ATRP to prepare PNIPAm resulted in polymers with broad polydisperisities [56], but this problem was circumvented by utilizing a more efficient ligand for the initiator complex [57]. 

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