A liquid crystal mixture with giant electrocaloric effect based on biaxial liquid crystal molecules

Abstract

The invention discloses a liquid crystal mixture with a giant electrothermal effect based on biaxial liquid crystal molecules. The biaxial liquid crystal molecules are added to a nematic liquid crystal mixture at the ratio; and the system comprises the following components in percentage by mass: 80%-95% of a nematic liquid crystal mixture with high dielectric anisotropy and 5%-20% of biaxial liquid crystal molecules. The preparation method comprises the following steps: evenly stirring the selected biaxial liquid crystal molecules and the nematic liquid crystal mixture with high dielectric anisotropy, so as to obtain the liquid crystal mixture with the giant electrothermal effect; and adding the biaxial liquid crystal molecules to the mixture, so as to play a role in induced orientation on mother liquid crystal molecules, thus the thermodynamic entropy change of the liquid crystal mixture under the electric field action is increased; the adiabatic temperature change is improved; and the maximal adiabatic temperature can reach 10.27 DEG C. The liquid crystal mixture has the advantages of good stability, low viscosity and fast electric field response.

Description

technical field [0001] The invention relates to the technical field of liquid crystal materials and refrigeration materials, in particular to a liquid crystal mixture with giant electrothermal effect based on biaxial liquid crystal molecules. Background technique [0002] The electrocaloric effect refers to the phenomenon that the temperature of a pyroelectric body will change when the permanent polarization intensity changes due to an external electric field under adiabatic conditions. It is the inverse effect of the pyroelectric effect. The most important application of electrocaloric effect is to use materials with electrocaloric effect to replace the steam condensation cycle mainly used in refrigeration at present. The available power of the compressor used in the steam condensation cycle is low, only 30% of the power is used for refrigeration, and the fluorine-based refrigeration materials used are the main source of the greenhouse effect. [0003] At present, ceramic...

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Problems solved by technology

However, the maximum adiabatic temperature change obtained by a single liquid crystal material is generally higher than room temperature, and an additional heating system needs to be added, which increases energy loss. In addition, the adiabatic temperature change obtained by a single liquid crystal material is generally low, which cannot meet actual needs.

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