Auxetic Liquid Crystal Elastomers: Overcoming Barriers to Scale-Up

Area of Science:

• Materials Science
• Polymer Chemistry
• Soft Matter Physics

Background:

• Auxetic behavior, characterized by a negative Poisson's ratio, has been observed in liquid crystal elastomers (LCEs).
• Previous fabrication methods for auxetic LCEs relied on mechanical strain or nonreactive templates, complicating manufacturing and scale-up.
• These methods often result in anisotropic shrinkage, limiting practical applications.

Purpose of the Study:

• To report the first synthesis of an auxetic LCE using surface alignment without a nonreactive template.
• To demonstrate a simplified and scalable manufacturing process for auxetic LCEs.
• To investigate the auxetic properties and their dependence on temperature.

Main Methods:

• Synthesis of LCEs with both terminally and laterally attached mesogens.
• Utilizing surface alignment for nematic ordering in precursors, eliminating the need for templates and washout steps.
• Characterization of auxetic behavior and its relationship with the glass transition temperature.

Main Results:

• Successful synthesis of an auxetic LCE via surface alignment, bypassing template-assisted methods.
• The developed LCE exhibits an auxetic threshold at 76% strain.
• The auxetic behavior shows a dependence on the glass transition temperature, consistent with existing literature.

Conclusions:

• This work presents a significant advancement in the fabrication of auxetic LCEs, offering a template-free and scalable approach.
• The developed material and method pave the way for broader applications of auxetic LCEs.
• Further research can build upon this simplified synthesis for advanced material design.