Synthesis and properties of arborescent polyisobutylene‐poly(ethylene oxide) graft copolymers: a comparison of linear and arborescent graft copolymer architectures

AbstractPolymer architecture can have a significant effect on the properties and potential applications of materials. In this study, arborescent polyisobutylene (PIB)‐poly(ethylene oxide) (PEO) graft copolymers with varying PEO content were synthesized from arborescent PIB‐co‐polyisoprene and compared with linear PIB‐PEO graft copolymers. By AFM imaging, phase separation was detected in a 48 wt% PEO arborescent copolymer. Tensile testing revealed that, in general, increasing PEO content led to increased tensile strength and Young's modulus but decreased elongation at break. Arborescent analogues exhibited lower elongation at break and lower strength compared with linear analogues but also less plastic deformation and yielding behaviour. Like linear analogues of comparable PEO content, films of the arborescent graft copolymers resisted the adsorption of rhodamine‐labelled fibrinogen, suggesting that they may also exhibit non‐fouling properties. Finally, the assembly of these amphiphilic copolymers in aqueous solution was investigated. Unlike the linear analogues, the sizes of the assemblies were not greatly affected by their method of preparation. This work demonstrates that it is possible to prepare PIB‐based materials with a wide range of interesting properties by tuning not only the content of PEO but also the architectures of the macromolecules. © 2014 Society of Chemical Industry