Composite film and preparation method thereof

Abstract

The invention relates to the technical field of radiation refrigeration, in particular to a composite film, a preparation method and application thereof. The preparation method of the composite film has the advantages of simple process, wide material selection and low cost. The obtained composite film has good refrigeration effect and good flexibility at the same time, is suitable for a variety ofapplication scenes, and has a wider application range. The composite film provided by the embodiment of the invention includes a transparent matrix membrane and radiators dispersed in the transparentmatrix membrane. The radiators include first waveband radiators and second waveband radiators, wherein the infrared emission peak of the first waveband radiators is located or covered in a waveband range of 8-10microm, the infrared emission peak of the second waveband radiators is located or covered in a waveband range of 10-13microm, and the average emission rates of the first waveband radiatorsand the second waveband radiators in the infrared radiation waveband are both greater than or equal to 90%, and the average absorption rates in the rest wavebands is less than or equal to 10%. The composite film provided by the embodiment of the invention can be used for preparation of refrigeration materials.

Description

technical field [0001] The invention relates to the technical field of radiation refrigeration, in particular to a composite membrane and a preparation method thereof. Background technique [0002] Those bands with high transmittance where electromagnetic waves are less reflected, absorbed and scattered through the atmosphere are called atmospheric windows. For example: 0.3-2.5 microns, 3.2-4.8 microns, and 8-13 microns, etc. Among them, most objects on the surface have good emissivity in the 8-13 microns band, that is, they can dissipate their own heat at 8-13 The form of micron electromagnetic waves is emitted through the atmospheric window to the outer space where the temperature is close to absolute zero, so as to achieve the purpose of self-cooling. This technology does not require external energy input, has no pollution to the environment, and has positive significance for improving the indoor thermal environment of buildings and environmental protection. [0003] Ho...

AI Technical Summary

Problems solved by technology

[0003] However, although most objects have good emissivity in the 8-13 micron waveband, they cannot achieve high reflectivity for the rest of the waveband (such as the visible light band, etc.), and the absorption of these heat covers the effect of radiation cooling. achieve cooling

In order to solve this problem, people have tried the research and development of a variety of composite materials. At present, the research and development are mainly in the following three forms. The first is to cover the surface of the metal material within the wavelength range of 8-13 microns Composite materials formed by materials with high emissivity, such as plating silicon dioxide, calcium fluoride, etc. on highly polished aluminum plates; Composite materials formed by coatings with high emissivity in the remaining wave bands (such as visible light bands, etc.), such as depositing zinc sulfide on the surface of polyethylene terephthalate (PET) plastics, etc.; studies have found that: the two composite materials The refrigeration effect is difficult to meet the actual needs. At the same time, these two composite materials are prepared by surface deposition, which makes the obtained composite materials more brittle, which is not conducive to practical applications; the third is a high emissivity in the atmospheric window. In the rest of the region (such as the visible light region, etc.), photonic crystal materials with high reflectivity, although this material has a good cooling effect, are expensive, and the lithography technology is complicated, so it is not suitable for industrial production and application.

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