Fig. 2: Synthesis of rotaxane-branched DPs PGn and the schematic illustration of their stimuli-responsive features.

Synthesis of macromonomers MGn by a controllable divergent strategy and corresponding rotaxane-branched DPs PGn through ROMP, and the anion-induced thickness modulation of PGn (n = 1, 2, 3). Reaction conditions: (I) (a) Bu4NF·3H2O, THF, r.t., 4 h, 91%; (b) 1, CuI, DCM/Et2NH, r.t., overnight, 78%; (II) (a) Bu4NF·3H2O, THF, r.t., 4 h, 88%; (b) 1, CuI, DCM/Et2NH, r.t., overnight, 65%.