Light‐Responsive Block Copolymer Particles with Persistent Shape Memory and Programmable Reconfiguration

Abstract

ABSTRACT Light‐responsive polymeric particles provide a versatile platform that can undergo precisely programmed shape and color transformations, offering opportunities for advanced multi‐level memory systems. We report a block copolymer (BCP) particle system that functions as a structural memory element by reversibly switching among distinct morphologies and retaining each state with long‐term stability. The incorporation of hydrazone‐based photoswitches into polystyrene‐ block ‐poly(2‐vinylpyridine) (PS‐ b ‐P2VP) particles enables reversible and light‐programmed transformations, governed by ( E )/( Z ) isomerization under dual‐wavelength irradiation at 410 and 365 nm. The photoisomerization modulates the charge‐transfer character of the N─Br interaction within P2VP domains, yielding three well‐defined and distinct morphologies: lamellar ellipsoids (dark), networked lamellae (410 nm), and surface‐wrapped discs (365 nm). These photoinduced morphologies can be reversibly switched over multiple cycles without detectable fatigue. Importantly, each programmed state persists as a metastable configuration over 30 days in the dark, retaining > 97% of its original morphology. Furthermore, the incorporation of domain‐selective fluorescent dyes enables the system to provide real‐time, color‐coded visual readout of its encoded states via Förster resonance energy transfer modulation, opening new avenues for multi‐level data storage with direct optical access.