Controlling the Number of Arms of Polymer Stars with a Fullerene C60 Core

Abstract

Pure di‐ and tetra‐adducts can be obtained by grafting polystyrene (PS) chains onto C₆₀ via an atom transfer radical addition. Stars with a C₆₀ core and exactly six PS arms of molar mass ranging from 1000 to several 100,000 are easily produced by adding an excess of PSLi to the fullerene. Tri‐ to penta‐adducts can be prepared by controlling the stoichiometry PSLi/C₆₀. The number of grafts on the fullerene can be extended to seven or eight by initiation of the anionic polymerization of an adequate monomer with a “living” hexa‐adduct or by grafting onto this latter an halogen terminated polymer.