Diblock Copolymers as Scaffolds for Efficient Functionalization via Click Chemistry

A set of different alkyne containing diblock copolymers based on 4-hydroxystyrene was synthesized by nitroxide mediated radical polymerization (NMRP), all with excellent control over the molecular composition and narrow molar mass distribution. The diblock copolymers consist of labile protected 4-hydroxystyrene motifs in one block and bear alkyne functionalities in each repeating unit of the second block, thus making the materials candidates for polymer analogous modification reactions by a very efficient cycloaddition reaction. The use of 4-(trimethylsilylpropargyloxy)styrene as monomer proved highly advantageous compared to 4-(trimethylsilylethynyl) styrene, first because high control was kept in the NMRP process and second because there was higher accessibility in the postmodification reaction. In fact, quantitative postmodification through Cu(I)-catalyzed cycloaddition reaction of the pending propargyloxy groups with bulky adamantane azide of the diblock copolymers was achieved, yielding microphase-separated materials with a rigid block.