Precisely Controllable Artificial Muscle with Continuous Morphing based on "Breathing" of Supramolecular Columns.

Area of Science:

• Materials Science
• Polymer Chemistry
• Soft Robotics

Background:

• Skeletal muscles achieve complex tasks via precise linear contraction.
• Existing liquid crystal polymer artificial muscles often exhibit discrete shape changes due to order-disorder transitions, limiting precise deformation.
• Achieving arbitrary and continuous shape morphing in artificial muscles remains a significant challenge.

Purpose of the Study:

• To present a novel photoresponsive hemiphasmidic side-chain liquid crystal polymer.
• To demonstrate a unique "breathing" columnar phase enabling continuous material morphing.
• To explore orthogonal control of material deformation using heat and light.

Main Methods:

• Synthesis of a novel photoresponsive hemiphasmidic side-chain liquid crystal polymer.
• Utilizing the polymer's columnar phase and negative thermal expansion for muscle-like actuation.
• Investigating irreversible isomerization of photoresponsive mesogens for phototunable bending and fluorescence changes.
• Demonstrating controllable arm-like bending motions based on orthogonal thermal and photic responses.

Main Results:

• The polymer exhibits a unique "breathing" columnar phase enabling continuous morphing.
• Confinement within the columnar assembly leads to cooperative side-chain and backbone movements, resulting in significant negative thermal expansion.
• The material shows temperature-controllable, muscle-like elongation/contraction in oriented polymer strips.
• Irreversible isomerization of mesogens induces synergistic phototunable bending and a high-contrast fluorescence change.
• Orthogonal responses to heat and light allow for controllable, arm-like bending motions.

Conclusions:

• The developed liquid crystal polymer offers continuous, precise deformation unlike previous artificial muscles.
• The material's ability to respond distinctly to heat and light enables sophisticated, controllable actuation.
• This work presents a promising material for advanced artificial muscles and intelligent soft robotics applications.