Autonomous Switching of Self-Propelled Motion Modes of Hinokitiol-Fueled Elastomer Matrices.

Programmable self-propelled motion underpins essential biological functions and serves as a powerful inspiration in the design of dynamic synthetic materials. While significant progress has been made in developing self-propelled systems, most existing strategies rely on external stimuli or the incorporation of coupled oscillatory chemical reactions to achieve mode switching. In contrast, approaches that enable intrinsic switching between motion modes─such as from continuous to oscillatory─without external control remain limited. In this study, we introduce a self-propelled disk utilizing hinokitiol as a surface-active "fuel" within a polystyrene elastomer matrix, floating on the water surface. Hinokitiol-containing disks exhibited spontaneous transitions from continuous to oscillatory movement, distinctly without the need for external inputs. By leveraging the phase transitions of hinokitiol and tuning the mesoscale structure of the polymer scaffold, we succeeded in modulating the duration of continuous motion and frequency of oscillation in the macroscopic motion of the disks. These findings demonstrate that life-like macroscopic motion can be systematically engineered by coordinating the molecular arrangement of fuel species and the mesoscale structures of the surrounding polymer scaffold, presenting a versatile molecular design approach for synthetic self-propelled materials.