Photo- and Humidity-Responsive Liquid Crystal Copolymer Actuators Fabricated via Vapor-Assisted Alignment.

Area of Science:

• Polymer Science
• Materials Science
• Soft Robotics

Background:

• Multi-stimuli responsive liquid crystal polymers (LCPs) are crucial for advanced applications like soft robots and actuators.
• Integrating non-mesogenic responsive groups into LCPs is challenging due to disrupted mesogen assembly and alignment difficulties.

Purpose of the Study:

• To develop a novel method for achieving uniform mesogen alignment in multiresponsive LCPs containing non-mesogenic groups.
• To demonstrate the fabrication of dual-responsive actuators using the developed alignment technique.

Main Methods:

• A vapor-assisted alignment method was employed during the film preparation process.
• Copolymers incorporating azobenzene mesogens and non-mesogenic poly(ethylene glycol) (PEG) were synthesized.
• The alignment of azobenzene mesogens was achieved in a homeotropic orientation.

Main Results:

• The vapor-assisted alignment method successfully facilitated uniform homeotropic alignment of azobenzene mesogens in PEG-containing copolymers.
• The resulting copolymer films exhibited dual-responsiveness, showing photodeformation (from azobenzene isomerization) and humidity-responsive deformation (from surface swelling).
• Dual-responsive smart blinds and bionic flower actuators were successfully fabricated, showcasing the practical application of the material.

Conclusions:

• The vapor-assisted alignment method offers a feasible approach for aligning mesogens in multiresponsive LCPs.
• This technique enables the creation of advanced materials with combined photo- and humidity-responsive properties.
• The developed LCPs hold significant potential for applications in soft robotics, sensors, and biomimetic devices.