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Trade-off effect between the stress and strain range in the soft elasticity of liquid crystalline elastomers

Polymer Journal volume 54, pages 1017–1027 (2022)Cite this article

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Abstract

For liquid crystal elastomers (LCEs), crosslinking is a stress reinforcing factor that sufficiently inhibits macroscopic deformation. In this study, coarse-grained molecular simulations were performed to systematically investigate the dependence of the stress–strain curves of LCEs on the crosslink density. For the unidirectionally oriented initial structure of LCEs, uniaxial elongation was performed in perpendicular or parallel directions. The perpendicularly elongated LCEs demonstrated a characteristic plateau region in the stress–strain curve, indicating soft elasticity. This plateau region corresponds to a large change in the orientational order parameter, indicating that the orientation of mesogens is closely related to soft elasticity. The strain region corresponding to the soft elasticity became narrower as the crosslink density increased. The change in the orientation order parameter also became steeper with increasing crosslink density. On the other hand, the stress values in the plateau region increased with increasing crosslink density. These results indicate a systematic trade-off between stress and strain in the soft elasticity of LCEs, which means that it is possible to select the optimal set of values of stress and the strain range through the crosslink density. Furthermore, the presence of optimal solvent and polymer chain densities that can increase the stress while extending the strain range is indicated.

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Acknowledgements

This paper is based on results obtained from a project (JPNP16010) commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

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  1. These authors contributed equally: Haruka Yasuoka, Kazuaki Z. Takahashi

Authors and Affiliations

  1. Research Association of High-Throughput Design and Development for Advanced Functional Materials, Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Ibaraki, Japan

    Haruka Yasuoka

  2. Panasonic Corporation, 3-1-1 Yagumo-naka-machi, Moriguchi City, 570-8501, Osaka, Japan

    Haruka Yasuoka

  3. Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Ibaraki, Japan

    Kazuaki Z. Takahashi & Takeshi Aoyagi

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  1. Haruka Yasuoka
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Correspondence to Kazuaki Z. Takahashi.

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Yasuoka, H., Takahashi, K.Z. & Aoyagi, T. Trade-off effect between the stress and strain range in the soft elasticity of liquid crystalline elastomers. Polym J 54, 1017–1027 (2022). https://doi.org/10.1038/s41428-022-00641-z

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