A Light‐Activated Polymer Composite Enables On‐Demand Photocontrolled Motion: Transportation at the Liquid/Air Interface

Swimming with the dolphins: Photodriven swimmers are achieved based on a bimorph composite structure of an azobenzene‐containing liquid‐crystalline polymer network (LCN) and Kapton. They show fast, continuous, and everlasting motion at the liquid/air interface under UV irradiation, enabling on‐demand control of motion, including an on‐off switch, velocity, and direction, at room temperature.

Abstract

Swimmers at liquid/air interfaces have drawn enormous attention because of their potential applications. Described herein is one novel light‐driven swimmer based on a bimorph composite structure of a photoresponsive liquid‐crystalline polymer network and a commercially available polyimide (Kapton). The motion of the swimmer can be controlled by photoirradiation. The bilayer‐structured film shows quickly photoinduced bending towards the Kapton side upon exposure to UV light, and recovers immediately after removal of light. When placed on a liquid surface, the swimmer propels itself continually though rhythmic beating the liquid like a dolphin moving forward with its tail fin. Besides, light‐powered rotation of the swimmer is successfully achieved by simply changing the length‐width ratio and the irradiation site, mimicking the function of a dolphin's pectoral fin. Combining the forward movement and rotation motion together, on‐demand directional control of the phot‐driven swimmer can be readily obtained at room temperature, showing promise for miniaturized units for transportation.

from A via a.sfakia on Inoreader http://bit.ly/2AR0Fgv