Liquid crystal elastomer shell actuators with negative order parameter

Area of Science:

• Soft Matter Physics
• Materials Science
• Polymer Science

Background:

• Liquid crystals (LCs) possess long-range orientational order, characterized by an order parameter $$.
• A significant portion of the order parameter range (^-1/₂ < 〈P₂〉 < 0) has remained experimentally inaccessible.
• Conventional liquid crystal elastomers (LCEs) exhibit specific optical and actuation properties based on their ordered state.

Purpose of the Study:

• To introduce the first material class exhibiting a negative liquid crystal order parameter (〈P₂〉 < 0) in its ground state.
• To explore the unique optical and actuation characteristics of these novel anti-ordered elastomers.
• To expand the accessible range of liquid crystallinity for fundamental research and technological applications.

Main Methods:

• Synthesis and characterization of novel elastomeric shells designed to exhibit anti-ordering.
• Measurement of optical properties to determine the order parameter and assess light-matter interactions.
• Evaluation of actuation responses under external stimuli to compare with conventional LCEs.

Main Results:

• Successful creation of the first material with a negative liquid crystal order parameter (〈P₂〉 < 0).
• Demonstration of optical and actuation characteristics that are opposite to those of conventional LCEs.
• Access to the previously secluded range of liquid crystallinity, specifically 〈P₂〉 < 0.

Conclusions:

• This work presents a new class of anti-ordered elastomers, providing access to a new regime of liquid crystallinity.
• The findings present new challenges and opportunities for soft matter physics research.
• The novel LCE actuators offer complementary functionalities for applications in soft robotics and beyond.