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

Area of Science:

• Soft robotics
• Photoresponsive materials
• Polymer science

Background:

• Azobenzene actuators are key in soft robotics and artificial muscles due to photoresponsive trans-cis isomerization.
• Achieving multiphase actuation (gas-liquid interface and liquid phase) with azobenzene materials remains a significant challenge.

Purpose of the Study:

• To develop a novel Janus azobenzene inverse opal membrane for efficient multiphase photoactuation.
• To overcome limitations in current azobenzene actuator designs for diverse environments.

Main Methods:

• Fabrication of a Janus membrane with a polydomain azobenzene inverse opal structure on one side and a monodomain bulk polymer on the other.
• Utilizing the inverse opal structure to enhance liquid-polymer interaction.
• Investigating actuation mechanisms including Marangoni effect and bubble propulsion.

Main Results:

• The proposed Janus membrane demonstrates controllable movement at the air-liquid interface via the Marangoni effect.
• The actuator exhibits forward propulsion in the liquid phase, driven by bubble propulsion under UV irradiation.
• The inverse opal structure effectively increases the surface area for liquid-polymer interactions, enhancing actuation performance.

Conclusions:

• The developed Janus azobenzene inverse opal membrane offers a versatile platform for multiphase photoactuation.
• This design significantly advances the capabilities of soft robots and artificial muscles in various environments.
• The fabrication method is simple and holds great potential for future photoactuator designs.