Reconfiguring handed shape-morphing and actuation in hydrogels via light-encoded rapid expansion

Abstract

Reconfiguring handedness in synthetic systems with spatiotemporal control and reversible behavior remains a fundamental challenge in bioinspired robotics and materials science—especially in structurally homogeneous materials that lack intrinsic chirality. Here, we demonstrate homogeneous photoactive hydrogels capable of ultrafast, programmable handed shape-morphing, including helices and twists, through spatially controlled light illumination. This transformation is driven by a photoexpansion exceeding 80,000% volumetric growth within 40 seconds, enabled by the synergistic combination of spiropyran photoisomerization and tailored polymer-network interactions. Deterministic strain mismatches at illuminated interfaces allow on-demand forming and shaping of handed architectures, which can be erased in darkness and reprogrammed reversibly with light. We further synchronize opposing handedness and complex tendril-like geometries in a single material, and exploit handedness to achieve self-propelled rotation for robotic locomotion. This work introduces a versatile method for adaptive, lifelike chirality in homogeneous matter, closing a key gap between biological shape-morphing and engineered soft robotics. Handedness in synthetic systems can be challenging to control. Here, the authors report the development of homogeneous hydrogels with programmable, handed shape morphing, including helices and twists, as a result of photoexpansion.