Mastering the Photothermal Effect in Liquid Crystal Networks: A General Approach for Self‐Sustained Mechanical Oscillators

Chemical networks and molecular switches dominate the area of research geared toward macroscopic motion of materials. A counter‐intuitive approach to create self‐sustained oscillation by light irradiation of ordinary photostabilizers in splay‐aligned liquid‐crystalline networks made from commercial mesogens is developed. Photostabilizers or any molecules that are able to quickly dissipate the absorbed light through heat, by vibrational and/or rotational modes, can reach self‐oscillating macroscopic motion where self‐shadowing plays a critical role. The mechanical self‐oscillation is linked to temperature oscillations and the asymmetric response over the film thickness. Only a localized responsive zone, acting as hinge, activates the oscillation of a beam‐shaped device. The outcome of this research is extended from UV to near‐IR actuation, making bulk applications to convert sunlight into mechanical work within reach.