Fast response dry-type artificial molecular muscles with [c2]daisy chains.

Area of Science:

• Materials Science
• Nanotechnology
• Biomimetic Engineering

Background:

• Biological systems utilize organized filaments like myosin and actin for contractile functions, converting chemical energy into mechanical work.
• Molecular machines inspired by biological systems offer potential for advanced actuation and robotics.

Purpose of the Study:

• To develop novel photoresponsive molecular actuators mimicking biological contractile systems.
• To investigate the actuation mechanisms and performance of rotaxane-based [c2]daisy chain compounds in hydrogel and xerogel forms.

Main Methods:

• Synthesis of [c2]AzoCD2 hydrogel and xerogel via polycondensation of four-armed poly(ethylene glycol) and a rotaxane [c2]daisy chain.
• Utilizing α-cyclodextrin as the host and azobenzene as the photoresponsive guest component.
• Investigating light-induced actuation through ultraviolet irradiation and quantifying response times and mechanical work.

Main Results:

• Developed photoresponsive actuators ([c2]AzoCD2 hydrogel and xerogel) based on rotaxane [c2]daisy chains.
• Demonstrated light-induced bending towards UV light, driven by the sliding motion of the [c2]daisy chain unit.
• Achieved significantly faster actuation in the dry [c2]AzoCD2 xerogel (7°/s) compared to the hydrogel (7°/3h), and successfully used the xerogel to lift an object.

Conclusions:

• Rotaxane-based [c2]daisy chains are effective components for creating photoresponsive molecular actuators.
• The dry-state [c2]AzoCD2 xerogel exhibits rapid and powerful actuation, suitable for performing mechanical work.
• These actuators offer a promising biomimetic approach for developing advanced soft robotics and light-driven devices.