Living radical polymerization different polymer architectures

The development of PPE synthetic chemistry makes the synthesis of PPEs with various structures possible. Recently, PPE-based polymers with different topological structures including linear random copolymers, block copolymers, star polymers, miktoarm polymers, and brush and hyperbranched polymers have been synthesized. Among them, linear homopolymers or random copolymers of PPEs are perhaps the most studied. Different block copolymers with AB, ABA, and ABC architectures have been synthesized by controlled ROP. By the combination of ROP of PPE with other controlled polymerization methods, such as living radical polymerization, or click chemistry, more complex architectures including miktoarm, comb, or graft copolymers can be synthesized. The richness of structures has allowed the convenient adjustment of material properties of PPE for biomedical applications. 

Several others methods also exhibiting a living character are now being used for the construction of branched macromolecular architectures. One of them, group transfer polymerization, is briefly mentioned in the text. Special efforts are being made presently to apply living radical polymerization to the synthesis of star-shaped polymers. The performance of the different methods has been compared recently [94]. 

Due to the advancements in polymer synthesis there are a number of controlled polymerization techniques available today and, therefore, the number of publications on tailor-made block copolymers has increased especially during the last decade. Besides the living anionic and, to a less extent, also cationic polymerizations various techniques of controlled radical polymerization have become popular. Also some works have been carried out establishing control in polycondensation and even coordination polymerization. Some of the different techniques have been also combined in block copolymer synthesis. Thus an increasing number of monomers have become accessible for the synthesis of tailor-made block copolymers of various chain architectures. 

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