Mikto-arm star block copolymers

The properties of these polymers have similarities with mikto-arm star block copolymers. 

Babin J, Taton D, Brinkmann M, Lecoimnandoux S (2008) Synthesis and self-assembly in bulk of linear and mikto-arm star block copolymers based on polystyrene and poly(glutamic acid). Macromolecules 41 1384-1392... 

Figure 20.4 AFM image in phase mode of the self-assembled lamellar structure of PS-b-PGA block copolymers. (Reprinted with permission from J. Babin, D. Taton, M. Brinkmann and S. Lecommandoux, Synthesis and self-assembly in bulk of linear and mikto-arm star block copolymers based on polystyrene and poly(glutamic acid), Macromolecules, 41, 4, 1384-1392, 2008. 2008 American Chemical Society.)...

The generic features of these approaches are known from experience in anionic polymerization. However, radical polymerization brings some issues and some advantages. Combinations of strategies (a-d) are also known. Following star formation and with appropriate experimental design to ensure dormant chain end functionality is retained, the arms may be chain extended to give star block copolymers (321). In other cases the dormant functionality can be retained in the core in a manner that allows synthesis of mikto-arm stars (324). 

Fig. 4 TEM images of CHCI3 cast of (a) AB-type diblock copolymer, (b) AB2-type mikto-arm star copolymer, (c) A2B-type mikto-arm star copolymer, and (d) (AB)3-type star block copolymer. The samples were stained with RUO4 prior to TEM measurement...

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