Ion-Induced Stretching of Low Generation Dendronized Polymers with Crown Ether Branching Units

Synthesis of the first (G1) and second generation (G2) dendronized macromonomers MG1 and MG2 with the dibenzo-24-crown-8 moiety as branching unit is reported. The corresponding dendronized polymers, the polymethacrylates PG1 and PG2, were synthesized by free radical polymerization using AIBN as initiator at 60−80 °C. Static and dynamic light scattering revealed a significant chain expansion upon complexation of these polymers’ crown ether side chains with K+ ions. It is concluded that electrostatic repulsion does not significantly contribute to the chain expansion because of excessive counterion binding even well below the Manning limit, as evidenced by 19F NMR and 1H−19F NOE experiments. R…