The present invention relates to arborescent polymers comprising isoolefins and styrenic monomers, as well as processes for making same. In particular, the invention relates to highly branched block copolymers comprising an arborescent core with a high glass-transition temperature (Tg) and branches attached to the core terminated in polymer endblock segments with a low Tg. The copolymers of the invention desirably exhibit thermoplastic elastomeric properties and, in one embodiment, are desirably suited to biomedical applications.
