Molecular Engineering of Mesogenic Constituents Within Liquid Crystalline Elastomers to Sharpen Thermotropic Actuation

• Published in: Advanced functional materials Vol. 31; no. 16
• Main Authors: McCracken, Joselle M., Donovan, Brian R., Lynch, Kelsey M., White, Timothy J.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.04.2021
• Subjects: Actuation; Consumer goods; Crystal structure; Crystallinity; Elastomers; liquid crystalline elastomers; Liquid crystals; materials chemistry; Materials science; Mechanical analysis; Monomers; Precursors; Robotics; soft robotics; Thermal response; Thermal stability; Thin films
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202100564

Liquid crystalline elastomers (LCE) are stimuli‐responsive materials with a distinguished mechanical response. LCE have been subject to numerous recent functional examinations in robotics, health sciences, and optics. The liquid crystallinity of the elastomeric polymer networks of LCE are largely derived from liquid crystalline monomer precursors. Recent reports have utilized commercially available liquid crystalline diacrylate monomers in chain extension reactions to prepare LCE. These reactions have been largely based on monomeric precursors originally to enhance the and thermal stability of optical films. Here, it is demonstrated that preparing LCE via a liquid crystalline diacrylate with reduced mesogen–mesogen interaction enhances and sharpens the thermotropic actuation of these materials. Robust composition‐response correlations are demonstrated in LCE prepared by three common synthetic methods. The enhanced thermotropic response of LCE prepared from this precursor increases the thermomechanical efficiency by sixfold. Accordingly, this work addresses important limitations in utilizing the thermal response of LCE in robotics, health care, and consumer goods. Numerous reports document liquid crystalline elastomers (LCE) based on commercially available liquid crystalline monomers containing three phenyl rings that demonstrate exceptional stimuli‐induced mechanical response in functional applications in robotics, health care, aerospace, and consumer goods. Here, a LCE monomer with reduced intermolecular coupling is incorporated to lower actuation onset temperature and enhance the thermomechanical efficiency of LCE sixfold.