Flexible transparent porous gold electric heating film and preparation method thereof

Abstract

The invention discloses a flexible transparent porous gold electric heating film and a preparation method thereof, and belongs to the technical field of electric heating films. The preparation method comprises the following steps: depositing a gold film on a substrate by adopting a magnetron sputtering method to prepare a gold / substrate composite film, vertically immersing the gold / substrate composite film in a polyurethane-polymethyl methacrylate solution, then pulling the gold / substrate composite film out of a liquid level, placing the gold / substrate composite film in a constant-temperature and constant-humidity chamber, and drying the gold / substrate composite film to obtain the gold / substrate composite film. A porous polyurethane-polymethyl methacrylate template / gold / substrate composite film is obtained; the porous polyurethane-polymethyl methacrylate / gold / substrate composite film is immersed in an etching solution for selective etching, and a porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film is prepared; and the porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film is immersed in a template removing solvent, the porous polyurethane-polymethyl methacrylate template layer is removed, and the flexible transparent porous gold electric heating film is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of electric heating films, and in particular relates to a flexible transparent porous gold electric heating film and a preparation method thereof. Background Art

[0002] With the widespread application of flexible wearable electronic technology, flexible electric heaters are gradually replacing traditional rigid electric heaters in fields such as sensors, medical equipment, and artificial intelligence. Transparent film heaters are mainly used in scenes that are prone to fogging, such as camera windows, car windows, and transparent glass curtain walls, to defrost, defog, and maintain a high light transmittance. However, in traditional transparent film heaters, the heat loss generated by the transparent electric heating film layer is large, and the efficiency of defrosting and defog needs to be further improved. As the core component of the electric heater, the electric heating film plays an important role in the heating effect, safety, portability, and comfort of the electric heater. Existing flexible electric heating films have inherent brittleness and rigidity, poor cutting accuracy and flexibility, and it is difficult to prepare micro electric heaters for curved heat source surfaces.

[0003] Invention patent CN110944418A discloses a multi-layer flexible transparent electric heating film, which adopts a method of depositing a metal conductive layer and a metal oxide dielectric layer on a flexible substrate. Although this method takes into account the defogging performance and heating performance, the preparation method is complicated and the transparency is low. Invention patent CN104883760B discloses a low-voltage transparent electric heating film, which adopts a method of directly bonding the graphene or carbon nanotube conductive layer to the film with UV glue. This method requires the setting of electrode bus bars, and the structure and process flow are relatively complicated and the cost is very high. Therefore, it is urgent to develop a flexible transparent electric heating film material with high transparency, simple processing technology, low cost, high stability and high safety. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a flexible transparent porous gold electric heating film and a preparation method thereof, which solves the problems in the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0007] A gold film is deposited on a substrate by magnetron sputtering to prepare a gold / substrate composite film;

[0008] The gold / substrate composite film is vertically immersed in a polyurethane-polymethyl methacrylate solution, and then the gold / substrate composite film is pulled out of the liquid surface, and then placed in a constant temperature and humidity chamber, and after drying, a porous polyurethane-polymethyl methacrylate template / gold / substrate composite film is obtained;

[0009] The porous polyurethane-polymethyl methacrylate / gold / substrate composite film is immersed in an etching solution for selective etching to prepare a porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film;

[0010] The porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film is immersed in a template removal solvent to remove the porous polyurethane-polymethyl methacrylate template layer to obtain a flexible transparent porous gold electric heating film.

[0011] Furthermore, the substrate is any one of polyethylene terephthalate, polyimide, polypropylene and polydimethylsiloxane.

[0012] Furthermore, the thickness of the gold film is 18-20 nm.

[0013] Furthermore, the solvent used in the polyurethane-polymethyl methacrylate solution is tetrahydrofuran, and the solution concentration is 22-24 g / L.

[0014] Furthermore, in the polyurethane-polymethyl methacrylate solution, the mass ratio of polyurethane to polymethyl methacrylate is 40:(5-7).

[0015] Furthermore, the temperature in the constant temperature and humidity chamber is 20-30°C, and the humidity is 85-95%.

[0016] Furthermore, the etching solution is an iodine / potassium iodide etching solution; the concentration of the iodine / potassium iodide etching solution is 2-3 g / L, and the etching time is 2-5 min.

[0017] Furthermore, the template solvent is acetone or N,N-dimethylformamide.

[0018] A flexible transparent porous gold electric heating film is prepared by adopting the above-mentioned method for preparing a flexible transparent porous gold electric heating film.

[0019] An electric heater comprises the above-mentioned flexible transparent porous gold electric heating film.

[0020] Beneficial effects of the present invention:

[0021] The present invention improves the porosity and the number of holes in the porous polymer template by setting an optimized ratio of polymer polyurethane and polymethyl methacrylate during the breathing pattern process, so as to prepare a porous gold electric heating film with high flexibility, high transparency, high electric heating performance, high stability and high safety characteristics, which has good application prospects in the field of flexible electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 is a microscope image of the flexible transparent porous electric heating film prepared in Example 1;

[0024] Figure 2 is the temperature-time curve of the flexible transparent electric heating film under different applied voltages in Example 1;

[0025] Figure 3 These are the electric heating steady-state temperatures and infrared thermal images of the flexible transparent electric heating film under different bending times in Example 1. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0028] S1, depositing a gold film on a substrate by magnetron sputtering to prepare a gold / substrate composite film;

[0029] S2, vertically immersing the gold / substrate composite film into a polyurethane-polymethyl methacrylate solution, then pulling the gold / substrate composite film out of the liquid surface at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber for 10 minutes, and after drying, a porous polyurethane-polymethyl methacrylate template / gold / substrate composite film is obtained;

[0030] S3, immersing the porous polyurethane-polymethyl methacrylate / gold / substrate composite film in an iodine / potassium iodide etching solution for selective etching to prepare a porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film;

[0031] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film in a template removal solvent to remove the porous polyurethane-polymethyl methacrylate template layer to obtain a flexible transparent porous gold / substrate electric heating film.

[0032] Among them, in S1, the substrate is: any one of polyethylene terephthalate, polyimide, polypropylene and polydimethylsiloxane; the thickness of the gold film is 18-20nm.

[0033] In S2, the solvent used for the polyurethane-polymethyl methacrylate solution is tetrahydrofuran, and the solution concentration is 22-24 g / L; wherein the mass ratio of polyurethane to polymethyl methacrylate is 40:(5-7).

[0034] In S2, the temperature in the constant temperature and humidity chamber is 20-30°C and the humidity is 85-95%.

[0035] In S3, the concentration of the iodine / potassium iodide etching solution is 2-3 g / L; wherein the mass ratio of iodine to potassium iodide is 1:1.3, and the etching time is 2-5 min.

[0036] In S4, the template solvent is acetone or N,N-dimethylformamide.

[0037] The technical scheme of the present invention is specifically described below by the following examples and comparative examples, wherein the sources of the raw materials used in the examples and comparative examples are as follows:

[0038]

[0039] Example 1

[0040] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0041] S1, a 20 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0042] S2, dissolving 0.4 g of polyurethane and 0.06 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 95%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0043] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide etching solution with a concentration of 2.5 g / L for 3 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0044] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0045] Example 2

[0046] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0047] S1, a 18 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0048] S2, dissolving 0.4 g of polyurethane and 0.06 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 95%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0049] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide etching solution with a concentration of 2.5 g / L for 3 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0050] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0051] Example 3

[0052] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0053] S1, a 20 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0054] S2, dissolving 0.4 g of polyurethane and 0.05 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 95%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0055] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide etching solution with a concentration of 2.5 g / L for 3 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0056] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0057] Example 4

[0058] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0059] S1, a 20 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0060] S2, dissolving 0.4 g of polyurethane and 0.07 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 95%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0061] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide etching solution with a concentration of 2.5 g / L for 3 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0062] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0063] Example 5

[0064] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0065] S1, a 20 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0066] S2, dissolving 0.4 g of polyurethane and 0.06 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 85%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0067] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide etching solution with a concentration of 2.5 g / L for 3 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0068] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0069] Example 6

[0070] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0071] S1, a 20 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0072] S2, dissolving 0.4 g of polyurethane and 0.06 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 95%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0073] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide etching solution with a concentration of 2 g / L for 5 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0074] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0075] Example 7

[0076] A method for preparing a flexible transparent porous gold electric heating film comprises the following steps:

[0077] S1, a 20 nm gold film was deposited on a polyethylene terephthalate (PET) transparent substrate by magnetron sputtering to prepare a gold / PET film.

[0078] S2, dissolving 0.4 g of polyurethane and 0.06 g of polymethyl methacrylate in 20 mL of tetrahydrofuran to obtain a polyurethane-polymethyl methacrylate solution; vertically immersing the gold / PET film in the polyurethane-polymethyl methacrylate solution, pulling it out of the solution at a speed of 180 cm / min, and then placing it in a constant temperature and humidity chamber (temperature 25° C., humidity 95%) for 10 min, and drying to obtain a porous polyurethane-polymethyl methacrylate template / gold / PET composite film;

[0079] S3, immersing the porous polyurethane-polymethyl methacrylate template / gold / PET composite film in an iodine / potassium iodide aqueous solution with a concentration of 3 g / L for 2 minutes; taking out the composite film and rinsing it with deionized water to obtain a porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film.

[0080] S4, immersing the porous polyurethane-polymethyl methacrylate template / porous gold / PET composite film in an acetone solution for 5 minutes; taking out the composite film, rinsing it with deionized water, and drying it to obtain a porous gold / polyethylene terephthalate electric heating film.

[0081] Comparative Example 1

[0082] The only difference between Comparative Example 1 and Example 1 is that in S1, a 25 nm gold film is deposited on a polyethylene terephthalate transparent substrate by a magnetron sputtering method.

[0083] Comparative Example 2

[0084] The only difference between Comparative Example 2 and Example 1 is that in S1, a 15 nm gold film is deposited on a polyethylene terephthalate transparent substrate by a magnetron sputtering method.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that in S2, the temperature in the constant temperature and humidity chamber is 25°C and the humidity is 60%.

[0087] Comparative Example 4

[0088] The difference between Comparative Example 4 and Example 1 is that in S2, the process of not placing the sample in a constant temperature and humidity chamber is removed.

[0089] Comparative Example 5

[0090] The difference between Comparative Example 4 and Example 1 is that in S2, the polymer solution does not use polymethyl methacrylate but only uses polyurethane.

[0091] Experimental testing

[0092] The prepared electric heating film was tested for square resistance and transmittance of the porous gold / PET films prepared in the above Examples 1-7 and Comparative Examples 1-5 using a four-probe square resistance meter and a UV-visible photometer.

[0093] The prepared porous gold / PET film was cut into 40mm×30mm samples, and copper foil conductive glue was used to connect the two ends of the sample as electrodes to obtain a single-layer electric heating device. A voltage of 6V was applied to the electrodes at both ends of the porous gold / PET film, and an infrared thermal imager was used to test the electric heating temperature and response time. The electric heating device was cyclically bent at a bending angle of 90° to obtain the device's bending resistance performance. If the device's electric heating performance is significantly attenuated after a certain number of bends, it is considered that the device has reached the maximum bending resistance performance. The square resistance, transmittance, electric heating temperature, response time and bending resistance of the porous gold / PET film are shown in Table 1.

[0094] Table 1 Performance tests

[0095]

[0096] like Figure 1 As shown, the sample prepared in Example 1 has a uniform microporous porous structure. As can be seen from Table 1, it has the characteristics of high conductivity, high transparency and high flexibility. Its square resistance is 1.41Ω / sq and its transmittance is 87%. Figure 2 As shown in Table 1, the electric heating temperature of the electric heating device at a working voltage of 6V is 103.9°C, and the response time is 4s; Figure 3 As shown in Table 1, the bending resistance can reach 10,000 times.

[0097] Combined with the test data in Table 1, the samples of Example 1 and Comparative Example 1 are compared. Since a thick layer of gold film sample is used in Comparative Example 1, it is not easy to form a porous gold structure with a hole-perforated structure during the etching process, so the transparency of the porous gold film sample is low and the bending resistance is poor. Comparative Example 1 and Comparative Example 2 samples, since a thin layer of gold film sample is used in Comparative Example 2, the gold film is easy to fall off in large pieces during the etching process to form a discontinuous structure, resulting in damage to the grid conductive structure of the porous gold film, so the number of porous gold structures obtained after etching is reduced, so the square resistance of the sample is significantly improved, the electric heating temperature is significantly reduced, and the response time is significantly improved. For the sample of Comparative Example 4, since the sample in Comparative Example 4 is not placed in a constant temperature and humidity chamber, it is difficult to form a porous polyurethane-polymethyl methacrylate template film with many hole-perforated structures, so the transparency of the porous gold film sample after etching is lower and the bending resistance is worse. Comparing the samples in Example 1 and Example 5, since only polyurethane polymer is used in Example 5, it is difficult to obtain a porous template layer with a perforated structure over a large area, that is, it is difficult to obtain a porous gold film, so the samples have low transparency and poor bending resistance.

[0098] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0099] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a flexible transparent porous gold electric heating film, characterized in that: The following steps are involved: A gold film is deposited on a substrate by magnetron sputtering to prepare a gold / substrate composite film; The gold / substrate composite film is vertically immersed in a polyurethane-polymethyl methacrylate solution, and then the gold / substrate composite film is pulled out of the liquid surface, and then placed in a constant temperature and humidity chamber, and after drying, a porous polyurethane-polymethyl methacrylate template / gold / substrate composite film is obtained; The porous polyurethane-polymethyl methacrylate / gold / substrate composite film is immersed in an etching solution for selective etching to prepare a porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film; The porous polyurethane-polymethyl methacrylate template / porous gold / substrate composite film is immersed in a template removal solvent to remove the porous polyurethane-polymethyl methacrylate template layer to obtain a flexible transparent porous gold electric heating film.

2. The method for preparing a flexible transparent porous gold electric heating film according to claim 1, characterized in that: The substrate is any one of polyethylene terephthalate, polyimide, polypropylene and polydimethylsiloxane.

3. The method for preparing a flexible transparent porous gold electric heating film according to claim 1, characterized in that: The thickness of the gold film is 18-20 nm.

4. The method for preparing a flexible transparent porous gold electric heating film according to claim 1, characterized in that: The solvent used in the polyurethane-polymethyl methacrylate solution is tetrahydrofuran, and the solution concentration is 22-24 g / L.

5. The method for preparing a flexible transparent porous gold electric heating film according to claim 4, characterized in that: In the polyurethane-polymethyl methacrylate solution, the mass ratio of polyurethane to polymethyl methacrylate is 40:(5-7).

6. The method for preparing a flexible transparent porous gold electric heating film according to claim 1, characterized in that: The temperature in the constant temperature and humidity box is 20-30° C., and the humidity is 85-95%.

7. The method for preparing a flexible transparent porous gold electric heating film according to claim 1, characterized in that: The etching solution is an iodine / potassium iodide etching solution; the concentration of the iodine / potassium iodide etching solution is 2-3 g / L, and the etching time is 2-5 min.

8. The method for preparing a flexible transparent porous gold electric heating film according to claim 1, characterized in that: The template solvent is acetone or N,N-dimethylformamide.

9. A flexible transparent porous gold electric heating film, characterized in that: The flexible transparent porous gold electric heating film is prepared by the preparation method of any one of claims 1 to 8.

10. An electric heater, characterized in that: It comprises the flexible transparent porous gold electric heating film as described in claim 9.

Images