A Facile Synthesis of Dynamic, Shape-Changing Polymer Particles

We herein report a new facile strategy to ellipsoidal block copolymer nanoparticles that exhibit a pH‐triggered anistropic swelling profile. In a first step, elongated particles with an axially stacked lamellae structure are selectively prepared by utilizing functional surfactants to control the phase separation of symmetric polystyrene‐b‐poly(2‐vinylpyridine) (PS‐b‐P2VP) in dispersed droplets. In a second step, the dynamic shape change is realized by cross‐linking the P2VP domains, thereby connecting glassy PS discs with pH‐sensitive hydrogel actuators. Let surfactants do the work: Controlling the shape and morphology of polystyrene‐b‐poly(2‐vinylpyridine) (PS‐b‐P2VP) particles through the use of tailored, mixed surfactant systems allows for the facile and selective preparation of ellipsoidal nanoparticles. Cross‐linking of the axially stacked P2VP lamellae domains allows the pH responsiveness of the 2VP moieties to be exploited with generation of unique shape‐ and structure‐responsive particles.