Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.

Mistry, D; Connell, S D; Mickthwaite, S L; Morgan, P B; Clamp, J H; Gleeson, H F

Mistry, D; Connell, S D; Mickthwaite, S L; Morgan, P B; Clamp, J H; Gleeson, H F.

Afiliación

Mistry D; School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK. pydam@leeds.ac.uk.
Connell SD; School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
Mickthwaite SL; Leeds Electron Microscopy and Spectroscopy Centre, School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, UK.
Morgan PB; Eurolens Research, University of Manchester, Manchester, M13 9PL, UK.
Clamp JH; UltraVision CLPL, Commerce Way, Leighton Buzzard, LU7 4RW, UK.
Gleeson HF; School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.

Nat Commun ; 9(1): 5095, 2018 12 04.

Article en En | MEDLINE | ID: mdl-30514842

RESUMEN

Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and avoid porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.

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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: Nat Commun Asunto de la revista: BIOLOGIA / CIENCIA Año: 2018 Tipo del documento: Article Pais de publicación: Reino Unido

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