Multiphase Janus Azobenzene Inverse Opal Membrane toward On-Demand Photocontrolled Motion.

Azobenzene actuators have generated extensive research investment in the field of soft robots, artificial muscles, etc., based on the typical photoresponsive trans-cis isomerization. However, it remains challenging to achieve multiphase actuation at the gas-liquid interface and liquid phase. To solve these problems, this paper demonstrated a simple fabrication method of a Janus azobenzene inverse opal membrane with one side having a polydomain azobenzene inverse opal structure and the other side having a monodomain bulk azobenzene polymer. The introduction of an inverse opal structure increases the interaction area between the liquid and polymer network. The proposed design can freely swim in any direction at the air-liquid interface based on the Marangoni effect or move forward in the liquid phase based on bubble propulsion under UV irradiation. This work is of great significance for the design and fabrication of multiphase photo actuators.