Automatic temperature-regulating intelligent thermal control composite film and preparation method thereof

Abstract

The present invention relates to the technical field of composite radiation films, specifically an intelligent thermal control composite film with automatic temperature regulation and a method for preparing the same. The composite film comprises a base film that is capable of temperature-controlled curling and deformation; a fiber film having a radiative heating effect is formed on top of the base film; the radiative heating layer fiber film is a composite material of heat-absorbing nanotubes and infrared-transparent polymers; and a layer of radiative cooling fiber film having high solar reflectivity and high infrared emissivity is formed under the base film; the radiative cooling layer fiber film is a composite material of nanoparticles and high infrared emissivity. Compared with the prior art, the composite film of the present invention has excellent radiation regulation performance. Its temperature-controlled deformation structure can automatically adjust its operating mode according to changes in ambient temperature without the need for any external drive device. Furthermore, the composite film has a simple structure, a wide range of material sources, and excellent mechanical properties. The preparation process is simple, enabling large-scale, low-cost production.

Description

Technical Field

[0001] The present invention relates to the field of composite radiation films, in particular to an automatic temperature-regulating intelligent heat-control composite film and a preparation method thereof. Background Art

[0002] With the rapid development of the human economy and society, energy consumption has increased significantly, leading to energy crises and ecological pollution. Consequently, passive radiative cooling has attracted increasing attention. This technology leverages the spectral properties of materials to reflect solar radiation within the 0.3-2.5μm wavelength range while simultaneously dissipating heat to the cooler exterior space through the 8-13μm "atmospheric window," achieving a cooling effect. This technology holds broad application prospects in areas such as personal thermal management, building energy conservation, and spacecraft thermal control.

[0003] In recent years, thermal control films and components that achieve single radiative heating or radiative cooling functions have emerged in an endless stream, but dynamically combining solar energy absorption and radiative cooling to cope with different external environmental changes is still very challenging. Among the currently known technologies, materials that can still produce effective thermal management in the face of strong sunlight have long been developed, but these infrared high-emissivity materials will continue to produce radiative cooling effects in the cold winter. In response to this situation, researchers have proposed many different solutions, including the preparation of composite films that can meet the requirements of radiative heating and radiative cooling respectively. However, external power supply or mechanical structures such as flipping are required to complete mode switching, and true intelligent control cannot be achieved.

[0004] Composite thin films are typically multi-layer structures, requiring processes such as vacuum filtration, magnetron sputtering, and vapor deposition. However, these thin film preparation processes are complex and expensive, making them difficult to achieve large-scale continuous production in industry.

[0005] Therefore, there is an urgent need to explore an intelligent thermal control film that can combine radiative heating and radiative cooling functions and can automatically switch working modes according to external environmental conditions, as well as to design a preparation method with simple process and suitable for large-scale production. Summary of the Invention

[0006] The present invention aims to address the shortcomings of existing technologies by providing an intelligent thermal control composite film with automatic temperature regulation and a method for its preparation. Specifically, the film has a simple structure, can simultaneously regulate visible and infrared wavelengths, and can automatically adjust radiative heating and cooling modes according to changes in the external environment. This film is applicable to a wide range of materials and exhibits excellent composite spectral and mechanical properties.

[0007] The technical solutions for achieving the purpose of the present invention are as follows:

[0008] An intelligent, temperature-controlled composite film with automatic temperature regulation is composed of a radiative cooling layer, a temperature-controlled deformation layer, and a radiative heating layer. The radiative heating layer is fixed to the surface of the temperature-controlled deformation layer to form an integrated structure, while the temperature-controlled deformation layer is partially fixed to the surface of the radiative cooling layer to facilitate curling and deformation.

[0009] Furthermore, the radiation cooling layer uses nanoparticles and infrared high-emissivity composite materials; the temperature-controlled deformation layer uses aluminum film and oriented polyethylene film with excellent ductility; and the radiation heating layer uses multi-walled carbon nanotubes and infrared transparent polymer materials.

[0010] Furthermore, the edge of the temperature-controlled deformation layer is bonded to the radiation cooling layer by a polymer adhesive, and the fixed portion is 10%-15% of the area of the temperature-controlled deformation layer.

[0011] Furthermore, the radiation cooling layer and the radiation heating layer are both fiber laminate structures prepared by electrospinning, and the temperature-controlled deformation layer is prepared by aluminum film and oriented polyethylene film using a low surface energy adhesive.

[0012] Furthermore, the nanoparticles in the radiative cooling layer include one or more of silicon dioxide, titanium oxide, aluminum oxide, or boron nitride, with a particle size of 0.2-1 μm. The infrared high-emissivity polymer in the radiative cooling layer includes any one of polyvinylidene fluoride, polylactic acid, and polydimethylsiloxane, with a fiber diameter of 0.2-2 μm.

[0013] Furthermore, the radiation heating layer is an infrared high-emissivity polymer material doped with nanoparticles, and the radiation cooling layer (1) is an infrared transparent polymer material doped with multi-walled carbon nanotubes.

[0014] Furthermore, the doped particles in the radiation heating layer are multi-walled carbon nanotubes with a particle size distribution of 0.1-0.5 μm, and the infrared transparent polymer is polymethyl methacrylate, polyamide-6 or polyethylene, etc. with a fiber diameter distribution of 0.2-2 μm.

[0015] The method for preparing an automatic temperature-regulating intelligent thermal control composite film is characterized by comprising the following steps:

[0016] S1. Preparation of temperature-controlled deformation layer:

[0017] Apply low surface energy adhesive to the surface of the aluminum film, then select an oriented polyethylene film of the same size and stick it on the surface, use a low-temperature roller to roll it flat, ventilate it for 3 hours, and wait for the adhesive to solidify, with the aluminum film as the upper surface and the polyethylene as the lower surface.

[0018] S2. Configure the spinning solution for the radiation heating layer:

[0019] An infrared transparent polymer is added to an organic solvent and stirred until completely dissolved to obtain an electrospinning solution A with a solid content of 8%-20%; multi-walled carbon nanotube particles are added to the electrospinning solution and stirred for 1-2 hours to obtain a uniformly dispersed radiant heating layer spinning solution.

[0020] S3. Preparation of radiant heating layer fiber membrane:

[0021] Using electrospinning equipment, a temperature-controlled deformation layer is laid on the bottom of the receiving device, the spinneret is facing one side of the aluminum film, and the electrospinning parameters are adjusted to obtain a radiation heating layer fiber membrane.

[0022] S4. Prepare the spinning solution for the radiation cooling layer:

[0023] The infrared high emissivity polymer is added to the organic solvent and stirred until completely dissolved to obtain an electrospinning solution B with a solid content of 8-15%. Nanoparticles are added to the electrospinning solution B and stirring is continued for 1-2 hours to obtain a uniformly dispersed radiation cooling layer spinning solution.

[0024] S5. Preparation of radiation cooling layer fiber membrane:

[0025] Spinning equipment is used to adjust electrospinning parameters and electrospinning is performed to obtain a radiation cooling layer fiber membrane.

[0026] S6. Multi-layer membrane structure combination:

[0027] A portion of the radiative cooling layer is bonded to one side of the oriented polyethylene using a polymer adhesive.

[0028] Furthermore, the organic solvent includes any one or a combination of dimethylformamide, dichloromethane, acetone, and formic acid.

[0029] Furthermore, in step S1, the thickness of the aluminum film is 10-20 μm, and the thickness of the oriented polyethylene is 40-80 μm.

[0030] Furthermore, in step S2, the mass ratio of carbon nanotubes to infrared transparent polymer is 10%-35%. In step S4, the mass ratio of nanoparticles to infrared high emissivity polymer is 10-15%.

[0031] Furthermore, the specific parameters of electrospinning in steps S3 and S5 are: temperature 20-30°C, humidity 50%-80%, spinning positive voltage 15-25kV, negative voltage -2-0kV, receiving distance 10-15cm, and propulsion speed 0.1-2mL / h.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) The film realizes automatic mode switching through a temperature-controlled deformation layer. After the aluminum film is combined with the oriented polyethylene, in summer or at high temperatures, the polyethylene has a higher expansion capacity than the aluminum film, which will produce a curling phenomenon, showing the underlying radiation cooling layer (1), producing a radiation cooling effect; in winter or at low temperatures, the deformation layer will return to its deformation, showing the radiation heating layer (3), producing a heat preservation effect; and the carbon nanotubes will enhance the thermal conductivity, making the surface temperature uniform, which is conducive to the deformation layer to produce uniform and controllable deformation.

[0034] (2) The radiant heating layer uses a combination of carbon nanotubes and infrared-transparent polymers, which can combine the high solar absorptivity of the carbon nanotubes with the low infrared emissivity of the polymer to improve thermal insulation performance. The solar radiation absorptivity and infrared emissivity of the radiant heating layer (3) can reach 0.81-0.91 and 0.25-0.35 respectively.

[0035] (3) The radiation cooling layer is made of nanoparticles such as silicon dioxide and polymers with high infrared emissivity. Silicon dioxide has a unique infrared phonon resonance and produces a Mie scattering effect on sunlight, which makes the radiation cooling layer have a high solar band reflectivity and infrared emissivity, reaching 0.95-0.99 and 0.90-0.93 respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure and deformation of the intelligent thermal control composite film with automatic temperature adjustment in the present invention.

[0037] Figure 2 This is a graph showing the reflectivity data of the radiation cooling layer in the present invention.

[0038] Figure 3 This is the emissivity data diagram of the radiation cooling layer in the present invention. DETAILED DESCRIPTION

[0039] The design idea of the present invention is to use the temperature control layer to realize automatic regulation of the working mode while taking into account the influence of sunlight and infrared bands.

[0040] The present invention will be further described in detail below in conjunction with the embodiments. The following examples are illustrated using specific materials to help those skilled in the art further understand the invention, but are not intended to limit the present invention in any form. Within the framework of the present invention, several adjustments and improvements can also be made, which all fall within the scope of protection of the present invention. The various raw materials, instruments and equipment involved in the present invention can all be purchased commercially.

[0041] The film preparation process of the present invention is simple. It rationally configures and screens radiation heating and radiation cooling materials, adopts a high-efficiency and low-cost electrospinning method to prepare the radiation heating layer 3 and the radiation cooling layer 1, and combines the aluminum film and the directionally deformed polyethylene through the difference in thermal expansion capacity to form a temperature-controlled deformation layer 2 that curls at high temperatures and is flat at low temperatures. Example

[0042] First, prepare the temperature-controlled deformation layer. Select 10cm*10cm aluminum film and oriented polyethylene film on both sides, use low surface energy adhesive to bond them, and then use a low-temperature roller to smooth them.

[0043] Next, a spinning solution for the radiant heating layer was prepared: PMMA was added to acetone and stirred until uniformly dissolved, yielding a spinning solution with a solids content of 15%. Multi-walled carbon nanotubes (MWCNTs) with a diameter of 10-20 nm were added to the spinning solution, achieving a CNT-to-PMMA ratio of 25%. Mechanical stirring was performed for 2 hours to obtain a uniform spinning solution.

[0044] Using electrospinning equipment, a temperature-controlled deformation layer was placed at the bottom, one side of the aluminum film faced the spinneret, the spinning temperature was set to 30°C, the humidity was 50%, the spinning positive voltage was 20kV, the negative voltage was -2kV, the receiving distance was 15cm, and the propulsion speed was 1.5mL / h. Electrospinning was performed to obtain a radiant heating film.

[0045] Next, a spinning solution for the radiative cooling layer was prepared: polylactic acid (PLA) was added to dichloromethane and stirred until uniformly dissolved, resulting in a spinning solution with a solid content of 12%. White silica powder with a diameter of 0.1-1.5 μm was added to the spinning solution, with a mass ratio of 10% silica to PLA. After mechanical stirring for 2 hours, a uniform spinning solution was obtained.

[0046] Electrospinning equipment was used to obtain a radiation cooling film by setting the spinning temperature to 30°C, the humidity to 80%, the positive voltage to 15kV, the negative voltage to -2kV, the receiving distance to 12cm, and the propulsion speed to 1.5mL / h.

[0047] The reflectivity of the radiation cooling layer 1 in the visible light band in the embodiment is as follows: Figure 2 As shown, it is as high as 0.99; the atmospheric window band emissivity data is as follows Figure 3 As shown, it is 0.97, so it has a highly efficient radiation cooling effect.

[0048] In the above embodiments, silicon dioxide can be replaced by titanium dioxide, aluminum oxide or boron nitride, polylactic acid can be replaced by polyvinylidene fluoride or polydimethylsiloxane, and PMMA can be replaced by polyamide-6 or polyethylene.

[0049] Finally, a polymer adhesive is used to fix the area of one side of the radiation cooling layer to the polyethylene side of the temperature-control deformation layer, and the fixed portion is 10%-15% of the area of the temperature-control deformation layer.

[0050] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An intelligent thermal control composite film with automatic temperature regulation, characterized by: It is composed of a radiation cooling layer (1), a temperature-controlled deformation layer (2), and a radiation heating layer (3); wherein the radiation heating layer (3) is fixed on the surface of the temperature-controlled deformation layer (2) to form an integrated structure, and the temperature-controlled deformation layer (2) is partially fixed on the surface of the radiation cooling layer (1) to facilitate curling deformation; Bonding the edge of the temperature-controlled deformation layer (2) to the radiation cooling layer (1) by a polymer adhesive, wherein the fixed portion is 10%-15% of the area of the temperature-controlled deformation layer (2); The radiation cooling layer (1) uses nanoparticles and infrared high-emissivity polymer materials; the temperature-controlled deformation layer (2) uses aluminum film with excellent ductility and oriented polyethylene film; and the radiation heating layer (3) uses multi-walled carbon nanotubes and infrared transparent polymer materials.

2. The automatic temperature-regulating intelligent thermal control composite film according to claim 1, characterized in that: The radiation heating layer (3) is an infrared high-emissivity polymer material doped with nanoparticles, and the radiation cooling layer (1) is an infrared transparent polymer material doped with multi-walled carbon nanotubes.

3. The automatic temperature-regulating intelligent thermal control composite film according to claim 1, characterized in that: The radiation cooling layer (1) and the radiation heating layer (3) are both fiber laminate structures prepared by electrostatic spinning; the temperature-controlled deformation layer (2) is prepared by aluminum film and oriented polyethylene film using a low surface energy adhesive.

4. The automatic temperature-regulating intelligent thermal control composite film according to claim 1, characterized in that: The nanoparticles in the radiation cooling layer (1) include one or more combinations of silicon oxide, titanium oxide or aluminum oxide, and boron nitride, and the equivalent particle size thereof is 0.2-2 μm; the infrared high-emissivity polymer of the radiation cooling layer (1) includes any one of polyvinylidene fluoride, polylactic acid, and polydimethylsiloxane, and the fiber diameter thereof is 0.2-2 μm.

5. The automatic temperature-regulating intelligent thermal control composite film according to claim 1, characterized in that: The doped particles in the radiation heating layer (3) are multi-walled carbon nanotubes with a particle size distribution of 0.1-0.5 μm, and the infrared transparent polymer is polymethyl methacrylate, polyamide-6 or polyethylene with a fiber diameter distribution of 0.2-2 μm.

6. The method for preparing the automatic temperature-regulating intelligent thermal control composite film according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Preparation of temperature-controlled deformation layer (2): Apply low surface energy adhesive to the surface of the aluminum film, then select an oriented polyethylene film of the same size and stick it on the surface, use a low-temperature roller to roll it flat, ventilate for 3 hours, and wait for the adhesive to solidify, with the aluminum film as the upper surface and the oriented polyethylene film as the lower surface; S2. Configure the spinning solution for the radiation heating layer: The infrared transparent polymer is added to the organic solvent and stirred until completely dissolved to obtain an electrospinning solution A with a solid content of 8%-20%. Multi-walled carbon nanotube particles are added to the electrospinning solution and stirred for 1-2 hours to obtain a uniformly dispersed radiant heating layer spinning solution. S3. Preparation of radiant heating layer (3) fiber membrane: Using electrospinning equipment, laying a temperature-controlled deformation layer on the bottom of the receiving device, making the spinneret face one side of the aluminum film, adjusting the electrospinning parameters, and obtaining a radiation heating layer (3) fiber membrane; S4. Prepare the spinning solution for the radiation cooling layer: Add the infrared high emissivity polymer to the organic solvent and stir until completely dissolved to obtain an electrospinning solution B with a solid content of 8-15%. Add the nanoparticles to the electrospinning solution B and continue stirring for 1-2 hours to obtain a uniformly dispersed radiative cooling layer spinning solution. S5. Preparation of radiation cooling layer (1) fiber membrane: Using electrospinning equipment and adjusting spinning parameters, a radiation cooling layer (1) fiber membrane is prepared; S6. Multi-layer membrane structure combination: A portion of the radiative cooling layer (1) is bonded to one side of the oriented polyethylene using a polymer adhesive.

7. The method for preparing the automatic temperature-regulating intelligent thermal control composite film according to claim 6, characterized in that: The organic solvent includes any one or a combination of dimethylformamide, dichloromethane, acetone, and formic acid.

8. The method for preparing the automatic temperature-regulating intelligent thermal control composite film according to claim 6, characterized in that: In step S1, the thickness of the aluminum film is 10-20 μm, and the thickness of the oriented polyethylene is 40-80 μm; in step S2, the mass ratio of the multi-walled carbon nanotubes to the infrared transparent polymer is 10%-35%; in step S4, the mass ratio of the nanoparticles to the infrared high-emissivity polymer is 10-15%; in steps S3 and S5, the specific electrospinning parameters are: temperature 20-30°C, humidity 50%-80%, spinning positive voltage 15-25 kV, negative voltage -2-0 kV, receiving distance 10-15 cm, and propulsion speed 0.1-2 mL / h.

Images