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Large Electrocaloric Effect in a Dielectric Liquid Possessing a Large Dielectric Anisotropy Near the Isotropic–Nematic Transition
Author(s) -
Qian XiaoShi,
Lu ShengGuo,
Li Xinyu,
Gu Haiming,
Chien LiangChy,
Zhang Qiming
Publication year - 2013
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201202686
Subject(s) - electrocaloric effect , materials science , liquid crystal , ferroelectricity , dielectric , ferroelectric polymers , anisotropy , phase transition , condensed matter physics , isothermal process , isotropy , polarization (electrochemistry) , ceramic , electric field , thermodynamics , chemical physics , composite material , optoelectronics , optics , chemistry , physics , quantum mechanics
The recent findings of large electrocaloric effects (ECEs) in ferroelectric polymers and in ferroelectric ceramic thin films have attracted great interest for developing new cooling cycles that are environmental friendly and have the potential to reach better efficiency than the existing vapor‐compression approach. Compared with these solid state ECE materials, a dielectric fluid with a large ECE can be more interesting because it may lead to new cooling cycles with simpler structures than these based on solid state ECE materials. Here it is shown that a large ECE can be realized in the liquid crystal (LC) 5CB near its nematic–isotropic (N‐I) phase transition. 5CB has a large dielectric anisotropy, which facilitates the electric‐field‐induced large polarization change. As a result, a large ECE, i.e., an isothermal entropy change of more than 23.6 J kg −1 K −1 is observed just above the N‐I transition.