Direct Observation of Biaxial Nematic Order in Auxetic Liquid Crystal Elastomers

• Published in: Materials Vol. 16; no. 1; p. 393
• Main Authors: Wang, Zhenming, Raistrick, Thomas, Street, Aidan, Reynolds, Matthew, Liu, Yanjun, Gleeson, Helen F
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31.12.2022; MDPI
• Subjects: Auxetic materials; Deformation; Elastomers; Freedericksz transitions; Glass substrates; Liquid crystals; Motion picture directors & producers; Nematic crystals; Order parameters; Poisson's ratio; Polymers; Polyvinyl alcohol; Raman spectra; Reduction; Spectrum analysis; Thickness; United Kingdom; negative Poisson ratio; auxetic material; biaxial nematic; Raman scattering; liquid crystal elastomer; mechanical Frèedericksz transition; biaxial order; conoscopy

Auxetic materials exhibit a negative Poisson's ratio, i.e., they become thicker rather than thinner in at least one dimension when strained. Recently, a nematic liquid crystal elastomer (LCE) was shown to be the first synthetic auxetic material at a molecular level. Understanding the mechanism...