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arXiv · 2012.05605

Tunability of the elastocaloric response in main-chain liquid crystalline elastomers

M. Lavrič·N. Derets·D. Črešnar·V. Cresta·V. Domenici·A. Rešetič·G. Skačej·M. Sluban·P. Umek·B. Zalar·Z. Kutnjak·B. Rožič
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Abstract

Materials exhibiting a large caloric effect could lead to the development of new generation of heat-management technologies that will have better energy efficiency and be potentially more environmentally friendly. The focus of caloric materials investigations has shifted recently from solid-state materials toward soft materials, such as liquid crystals and liquid crystalline elastomers. It has been shown recently that a large electrocaloric effect exceeding 7 K can be observed in smectic liquid crystals. Here, we report on a significant elastocaloric response observed by direct elastocaloric measurements in main-chain liquid crystal elastomers. It is demonstrated that the character of the nematic to paranematic/isotropic transition can be tuned from the supercritical regime towards the first-order regime, by decreasing the density of crosslinkers. In the latter case, the latent heat additionally enhances the elastocaloric response. Our results indicate that a significant elastocaloric response is present in main-chain liquid crystalline elastomers, driven by stress fields much smaller than in solid elastocaloric materials. Therefore, elastocaloric soft materials can potentially play a significant role as active cooling/heating elements in the development of new heat-management devices.

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M. Lavrič, N. Derets, D. Črešnar, V. Cresta, V. Domenici, A. Rešetič, G. Skačej, M. Sluban, P. Umek, B. Zalar, Z. Kutnjak, B. Rožič. 2020-12-10. Tunability of the elastocaloric response in main-chain liquid crystalline elastomers. https://doi.org/10.1080/02678292.2020.1786177

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