A liquid diode flexible evaporator based on copper hydroxide and its preparation method and application

Abstract

The present invention discloses a liquid diode flexible evaporator based on copper hydroxide, as well as a preparation method and application thereof, belonging to the technical field of solar interface evaporators. The preparation method comprises the following steps: using Ar as a sputtering gas to remove impurities on a polymer substrate to obtain a clean polymer substrate; performing a pre-sputtering treatment on a Cu target to obtain a Cu target with the oxide layer on the target surface removed; sputtering the Cu target on the clean polymer substrate using a DC power supply to obtain a single-sided copper-plated polymer material; immersing the single-sided copper-plated polymer material in a mixed solution of sodium hydroxide and ammonium persulfate to obtain a liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side; cleaning the liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side to a set pH value, and then spreading the liquid diode photothermal absorption material on a support, with the side without copper hydroxide nanoneedles growing in contact with the support, to obtain a liquid diode flexible evaporator.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar interface evaporators, and in particular relates to a liquid diode flexible evaporator based on copper hydroxide, a preparation method and an application thereof. Background Art

[0002] Water scarcity has become a serious global challenge. Producing clean drinking water from seawater or wastewater offers an effective strategy for alleviating this scarcity. Current methods, such as reverse osmosis, multi-stage distillation, and multi-stage flash evaporation, rely primarily on electricity, consuming energy and causing environmental pollution.

[0003] In recent years, utilizing clean, environmentally friendly, abundant, and sustainable solar energy to replace electricity for seawater desalination has become an effective solution to water resource shortages. Solar-driven water evaporation technology has evolved through heating methods such as bottom evaporation, bulk evaporation, and interface evaporation. Among these, solar-driven interface steam generation (SDIG) technology heats only a localized area of ​​water with minimal heat loss, and has therefore been widely studied. In SDIG systems, a rational structural design to ensure enhanced light absorption, excellent water transport, and heat utilization is particularly important for efficient solar steam generation. Excellent water transport is key to ensuring efficient seawater desalination. Most water supply channels used in interface evaporation systems are bidirectional. In this structure, the continuous bidirectional transport of brine causes significant heat losses, reducing evaporation efficiency. Summary of the Invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a liquid diode flexible evaporator based on copper hydroxide, as well as a preparation method and application. The flexible photothermal evaporator prepared has excellent one-way water transport function and achieves the synergistic effect of high absorption rate and low heat loss.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing a liquid diode flexible evaporator based on copper hydroxide, comprising the following steps:

[0007] S1: Using Ar as sputtering gas to remove impurities on the polymer substrate to obtain a clean polymer substrate; pre-sputtering treatment is performed on the Cu target to obtain a Cu target with the oxide layer on the target surface removed;

[0008] S2: On a clean polymer substrate, a Cu target is sputtered under DC power supply conditions to prepare a single-sided copper-plated polymer material;

[0009] S3: Immersing the single-sided copper-plated polymer material in a mixed solution of sodium hydroxide and ammonium persulfate to obtain a liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side;

[0010] S4: The liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side is cleaned to a set pH value and then spread on a support. The side of the liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side where no copper hydroxide nanoneedles are grown contacts the support to obtain a liquid diode flexible evaporator.

[0011] In a specific implementation process, in S1, the polymer substrate is carbon fiber cloth.

[0012] In a specific implementation process, in S1, the process of using Ar as a sputtering gas to remove impurities on the polymer substrate to obtain a clean polymer substrate is as follows:

[0013] At a first set vacuum degree, Ar is introduced as a sputtering gas, and the sputtering is carried out in an Ar plasma atmosphere for a first set time; wherein the first set vacuum degree is 1.8×10 -3 Pa or less; the first set time is 10 to 20 minutes; the bias voltage during the bombardment is 450V and the air pressure is 5Pa.

[0014] In a specific implementation process, in S1, the process of performing pre-sputtering treatment on the Cu target to obtain a Cu target with the oxide layer on the surface of the target material removed is as follows:

[0015] Under the second set vacuum degree, the sputtering power value is set and then the sputtering is performed for the second set time; the second set vacuum degree is 0.6 Pa, the sputtering power value is 100 W, and the second set time is 10 to 20 minutes.

[0016] In the specific implementation process, in S2, the process parameters of the DC power supply condition are as follows: the current of the DC power supply condition is 0.2A; the sputtering time is 15 to 60 minutes; the sputtering vacuum is 0.6Pa; and the sputtering power value is 100W.

[0017] In a specific implementation process, in S3, the mass ratio of sodium hydroxide to ammonium persulfate in the mixed solution is (2.6-2.9): (0.4-0.7).

[0018] In a specific implementation process, in S4, the cleaning is performed using deionized water; the set pH value is 7; and the support is PF polyester cloth.

[0019] In a specific implementation process, in S4, the liquid diode flexible evaporator further includes a support base, the support body is arranged on the support base, and the support base is polystyrene foam.

[0020] The present invention provides a liquid diode flexible evaporator prepared according to any one of the methods for preparing a liquid diode flexible evaporator based on copper hydroxide.

[0021] The present invention also provides an application of the liquid diode flexible evaporator in seawater desalination.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses a preparation method of a liquid diode flexible evaporator based on copper hydroxide, which uses a Cu target to sputter on a polymer substrate to form a Cu layer with a certain thickness. Cu is densely stacked in the form of nanorods on the surface of the polymer substrate, providing a precursor for the subsequent growth of copper hydroxide nanoneedles. Secondly, the growth of copper hydroxide nanoneedles can be achieved under room temperature conditions. Ammonium persulfate is used as an oxidant to oxidize the copper layer. Further, copper ions react with hydroxide ions of sodium hydroxide to generate copper hydroxide, which is combined with a self-floating support body for application. It has good thermal insulation properties and can avoid energy loss caused by heat conduction during evaporation. Due to the uniqueness and superiority of material selection and preparation technology, the evaporator of the present invention has excellent photothermal conversion performance. Moreover, the prepared material has hydrophilic copper hydroxide nanoneedles on one side and a superhydrophobic polymer on the other side. The two sides show different wettability, which ensures the excellent one-way water transport channel of the evaporator during the desalination process and reduces heat loss during water transport. In addition, the material is placed on the support body to form an air insulation layer, further reducing heat loss and increasing photothermal conversion efficiency.

[0024] The present invention adopts a simple preparation method to prepare a liquid diode flexible evaporator with excellent one-way water transport function, realizing the synergistic effect of photothermal materials with high absorptivity and low heat loss.

[0025] The present invention discloses a liquid diode flexible evaporator manufactured using the aforementioned preparation method. This evaporator exhibits excellent one-way water transport, enabling water to be transported upward from the lower hydrophobic layer to the upper hydrophilic layer without flowing back downward. This achieves one-way water permeability and provides a novel evaporation structure for solar-driven interfacial evaporation technology. Therefore, the liquid diode flexible evaporator described in the present invention can be used in seawater desalination. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1Figures (a) and (b) are SEM images of the flexible material of the present invention at magnifications of 2000x and 20,000x, respectively; Figure (c) is an SEM image of the carbon fiber cloth coated with a Cu layer; and Figures (d), (e), and (f) are SEM images of the carbon fiber cloth with copper hydroxide nanoneedles at magnifications of 2000x, 4000x, and 8000x, respectively.

[0027] Figure 2 The mass change curves of the liquid diode flexible evaporator of the present invention and the original carbon fiber sample were placed in 3.5wt% salt water under 1 light intensity;

[0028] Figure 3 These are water contact angle test graphs of the carbon fiber cloth, the carbon fiber cloth plated with a Cu layer, and the carbon fiber cloth with copper hydroxide nanoneedles (front and back surfaces) described in the present invention. DETAILED DESCRIPTION

[0029] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0030] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0031] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0032] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0033] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0034] The invention provides a liquid diode flexible evaporator based on copper hydroxide, and a preparation method and application thereof.

[0035] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0036] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0037] The present invention discloses a method for preparing a liquid diode flexible evaporator based on copper hydroxide, which comprises the following steps:

[0038] 1) cleaning the polymer substrate to obtain a clean polymer substrate; using Ar as a sputtering gas to remove impurities on the clean polymer substrate; performing a pre-sputtering treatment on a Cu target to obtain a Cu target with the oxide layer on the target surface removed;

[0039] 2) sputtering a Cu target on a clean polymer substrate under direct current power conditions to prepare a single-sided copper-plated polymer material (a polymer material having a Cu coating on one side);

[0040] 3) Immersing the single-sided copper-plated polymer material in a mixed solution of sodium hydroxide and ammonium persulfate to prepare a flexible photothermal absorption material containing Cu(OH)2 nanoneedles on one side, namely, a liquid diode photothermal absorption material;

[0041] 4) The flexible photothermal material, the PF polyester cloth support and the polystyrene foam support base are assembled to prepare a liquid diode flexible evaporator.

[0042] The liquid diode flexible evaporator prepared by the present invention has an excellent one-way water transport function, reduces heat loss, and achieves high evaporation efficiency, and can therefore be used in seawater desalination.

[0043] The polymer substrate is preferably carbon fiber cloth.

[0044] In the specific implementation process, the preparation process of the Cu(OH)2-CFC liquid diode flexible evaporator is as follows:

[0045] 1. Preparation of Cu(OH)2-CFC flexible light and heat absorption material:

[0046] Step 1: Clean the carbon fiber cloth (CFC) substrate

[0047] In a numerically controlled ultrasonic cleaner with a frequency of 30 to 50 kHz, the polymer substrate of CFC was cleaned with deionized water and ethanol in sequence for 30 minutes, and then placed in an oven for drying at a drying temperature of 40 to 50° C. to obtain a clean CFC substrate.

[0048] Step 2: Magnetron sputtering to obtain Cu-CFC

[0049] A dual-chamber reactive magnetron sputtering instrument was used to prepare the samples, and the chamber was evacuated using a mechanical pump and a molecular pump, with a vacuum degree of up to 10 -4 Pa, and equipped with corresponding water circulation system, bias plasma cleaning system, RF power supply, DC power supply, sample rotation stage, etc. During the sputtering process, the polymer substrate CFC substrate is placed on the sample stage at the upper end. The polymer substrate CFC temperature is 25℃ and the rotation speed is fixed at 9r / min. The sputtering target is installed in an inclined manner to ensure that the entire substrate surface is coated. Ar can be introduced into the sputtering chamber. First, the vacuum degree of the sputtering chamber is evacuated to a high vacuum of 1.8×10 -3 Pa, and then Ar is introduced as sputtering gas, and bombarded for 10 to 20 minutes in an Ar plasma atmosphere to remove impurities on the CFC film and improve the bonding strength between the coating and the polymer substrate. The bias voltage is set to 450V and the gas pressure is set to 5Pa.

[0050] Then, the pressure in the vacuum chamber was adjusted to the required low vacuum pressure of 0.6 Pa for sputtering, and the sputtering power of the power supply was set to 100 W. Under this condition, the Cu target was pre-sputtered for 10 to 20 minutes to remove the oxide layer on the target surface and improve the purity of the deposit.

[0051] Finally, the shutter is opened, causing a glow discharge on the Cu target surface. The sputtered particles are then deposited onto the substrate surface under the action of an electric field. Specifically, the Cu target is sputtered for 15 to 60 minutes under a DC power supply to obtain a Cu layer of a certain thickness, resulting in a Cu coating of a certain thickness. The sputtering parameters for the Cu target include ensuring that the pressure in the vacuum chamber reaches the required high vacuum pressure of 0.6 Pa, setting the sputtering power of the power supply to 100 W, and starting the power supply.

[0052] Among them, the DC power supply conditions include: current 0.2A.

[0053] Step 3: Grow nanoneedles at room temperature to obtain Cu(OH)2-CFC

[0054] First, the Cu-CFC obtained in step 2 above was cut into the required size (2*2 cm).

[0055] Secondly, weigh granular sodium hydroxide and ammonium persulfate powder in a mass ratio of (2.6-2.9): (0.4-0.7) and 100 mL of deionized water, and stir at room temperature for 30-50 minutes to obtain a mixed solution of sodium hydroxide and ammonium persulfate.

[0056] Then, a 2x2cm Cu-CFC was immersed in a mixture of sodium hydroxide and ammonium persulfate for 10-30 minutes to grow copper hydroxide nanoneedles, resulting in Cu(OH)2-CFC. The Cu-CFC was then rinsed repeatedly with deionized water until the pH reached 7.

[0057] After the above steps, the flexible photothermal absorption material of Cu(OH)2-CFC was obtained.

[0058] 2. Assemble the liquid diode evaporator:

[0059] First, cut clean polystyrene foam into a cylindrical shape with a diameter of 2.5 cm and a thickness of 0.5 cm. Five holes were then made in sequence on the surface. Pre-cut PF polyester cloths were inserted into the holes one by one, leaving 0.2 cm of the PF polyester cloth exposed from the end of the polystyrene foam. The supports consisted of five pieces of PF polyester cloth measuring 1 x 1.5 x 0.05 cm in length, width, and thickness, respectively.

[0060] Then, Cu(OH)2-CFC was placed on the above-mentioned PF polyester cloth, wherein the side with Cu(OH)2 nanoneedles was facing upward, and the other side of the untreated polymer cloth was facing downward and in contact with the polyester cloth, with a contact area of ​​0.05 cm 2 .

[0061] 3. Solar steam experiment:

[0062] A 3.5wt% saline solution was used to simulate seawater concentration, and a xenon lamp (CEL-HXF300, AM1.5 filter) was used to simulate sunlight. The mass change during evaporation was measured using an electronic microbalance (AR224CN) with an accuracy of 0.0001g and recorded using SPDC data acquisition V2.01 software on a personal computer (PC). A solar evaporation experimental platform was constructed. Analysis and calculations were performed to determine the evaporation efficiency of the saline solution under the experimental conditions, as well as the photothermal conversion efficiency of the carbon foam, allowing for photothermal performance studies.

[0063] Pour an appropriate amount of 3.5 wt% salt water into a beaker, place the liquid diode flexible evaporator into the salt water, and fix the sample so that it does not sink into the salt water. Place all the devices on a precision electronic balance and monitor the mass change caused by water evaporation in real time. -2 ), to conduct solar steam generation tests.

[0064] Example 1

[0065] 1. Preparation of Cu(OH)2-CFC liquid diode flexible evaporator:

[0066] (1) Cleaning CFC substrate

[0067] In a numerically controlled ultrasonic cleaner with a frequency of 30 kHz, the polymer substrate of CFC was cleaned with deionized water and ethanol for 30 min and 30 min, respectively, and then placed in an oven for drying at a drying temperature of 40°C to obtain a clean CFC substrate.

[0068] (2) Cu-CFC obtained by magnetron sputtering

[0069] The present invention adopts a dual-chamber reactive magnetron sputtering instrument to prepare samples, and uses a mechanical pump and a molecular pump to evacuate the chamber, and the vacuum degree can reach 10 -4 Pa, and is equipped with a corresponding water circulation system, bias plasma cleaning system, RF power supply, DC power supply, sample rotation stage, etc. During the sputtering process, the polymer substrate CFC substrate is placed on the upper sample stage. The polymer substrate CFC temperature is 25°C and the rotation speed is fixed at 9r / min. The sputtering target is installed at an angle to ensure that the entire substrate surface is coated. Ar can be introduced into the sputtering chamber.

[0070] The present invention sputters the Cu target under the condition of direct current power supply.

[0071] First, the vacuum degree of the sputtering chamber was pumped to a high vacuum of 1.8×10 -3 Pa, and then Ar is introduced as sputtering gas, and bombarded for 10 minutes in an Ar plasma atmosphere to remove impurities on the CFC film and improve the bonding strength between the coating and the polymer substrate, wherein the bias voltage is set to 450V and the gas pressure is set to 5Pa.

[0072] Then, the pressure in the vacuum chamber was adjusted to the required low vacuum pressure of 0.6 Pa for sputtering, and the sputtering power of the power supply was set to 100 W. Under this condition, the Cu target was pre-sputtered for 10 minutes to remove the oxide layer on the target surface and improve the purity of the deposit.

[0073] Finally, the baffle is opened, causing a glow discharge on the Cu target surface. The sputtered particles are then deposited onto the substrate surface under the action of an electric field. Specifically, the Cu target is sputtered for 15 minutes under a DC power supply to obtain a Cu layer of a certain thickness, resulting in a Cu coating of a certain thickness. The sputtering parameters for the Cu target include ensuring that the pressure in the vacuum chamber reaches the required high vacuum pressure of 0.6 Pa, setting the sputtering power of the power supply to 100 W, and starting the power supply.

[0074] Among them, the DC power supply conditions include: current 0.2A.

[0075] (3) Cu(OH)2-CFC nanoneedles grown at room temperature

[0076] First, the Cu-CFC obtained in step 2 above was cut into the required size (2*2 cm).

[0077] Next, 2.6 g of granular sodium hydroxide, 0.4 g of ammonium persulfate powder, and 100 mL of deionized water were weighed and stirred at room temperature for 30 minutes to obtain a mixed solution of sodium hydroxide and ammonium persulfate.

[0078] Then, a 2x2cm Cu-CFC was immersed in a mixture of sodium hydroxide and ammonium persulfate for 10 minutes to grow copper hydroxide nanoneedles, resulting in Cu(OH)2-CFC. The Cu-CFC was then rinsed repeatedly with deionized water.

[0079] 2. Assemble the Liquid Diode Evaporator

[0080] First, clean polystyrene foam was cut into a cylindrical shape with a diameter of 2.5 cm and a thickness of 0.5 cm. Five holes were then made in sequence on the surface of the cylinder. The pre-cut PF polyester cloth was inserted into the holes one by one, with the PF polyester cloth protruding 0.2 cm from the end surface of the polystyrene foam.

[0081] Then, Cu(OH)2-CFC was placed on the above-mentioned PF polyester cloth, wherein the side with Cu(OH)2 nanoneedles faced upward and the other side of the untreated polymer cloth faced downward and contacted the polyester cloth.

[0082] After the above steps, a liquid diode flexible evaporator of Cu(OH)2-CFC was obtained.

[0083] 3. Solar steam experiment

[0084] The evaporation rate of the liquid diode flexible evaporator obtained in this example under 1 sun is 1.39 kg m -2 h -1 .

[0085] Example 2

[0086] 1. Preparation of Cu(OH)2-CFC liquid diode flexible evaporator:

[0087] (1) Cleaning CFC substrate

[0088] In a numerically controlled ultrasonic cleaner with a frequency of 50 kHz, the polymer substrate of CFC was cleaned with deionized water and ethanol for 30 min and 30 min, respectively, and then placed in an oven for drying at a drying temperature of 50°C to obtain a clean CFC substrate.

[0089] (2) Cu-CFC obtained by magnetron sputtering

[0090] The present invention adopts a dual-chamber reactive magnetron sputtering instrument to prepare samples, and uses a mechanical pump and a molecular pump to evacuate the chamber, and the vacuum degree can reach 10 -4 Pa, and is equipped with a corresponding water circulation system, bias plasma cleaning system, RF power supply, DC power supply, sample rotation stage, etc. During the sputtering process, the polymer substrate CFC substrate is placed on the upper sample stage. The polymer substrate CFC temperature is 25°C and the rotation speed is fixed at 9r / min. The sputtering target is installed at an angle to ensure that the entire substrate surface is coated. Ar can be introduced into the sputtering chamber.

[0091] The present invention sputters the Cu target under the condition of direct current power supply.

[0092] First, the vacuum degree of the sputtering chamber was pumped to a high vacuum of 1.8×10 -3 Pa, and then Ar is introduced as sputtering gas, and bombarded for 20 minutes in an Ar plasma atmosphere to remove impurities on the CFC film and improve the bonding strength between the coating and the polymer substrate, wherein the bias voltage is set to 450 V and the gas pressure is set to 5 Pa.

[0093] Then, the pressure in the vacuum chamber was adjusted to the required low vacuum pressure of 0.6 Pa for sputtering, and the sputtering power of the power supply was set to 100 W. Under this condition, the Cu target was pre-sputtered for 20 minutes to remove the oxide layer on the target surface and improve the purity of the deposit.

[0094] Finally, the shutter is opened, causing a glow discharge on the Cu target surface. The sputtered particles are then deposited onto the substrate surface under the action of an electric field. Specifically, the Cu target is sputtered for 30 minutes under a DC power supply to obtain a Cu layer of a certain thickness, resulting in a Cu coating of a certain thickness. The sputtering parameters for the Cu target include setting the pressure in the vacuum chamber to the required high vacuum pressure of 0.6 Pa, setting the sputtering power of the power supply to 100 W, and starting the power supply.

[0095] Among them, the DC power supply conditions include: current 0.2A.

[0096] (3) Cu(OH)2-CFC nanoneedles grown at room temperature

[0097] First, the Cu-CFC obtained in step 2 above was cut into the required size (2*2 cm).

[0098] Next, 2.7 g of granular sodium hydroxide, 0.5 g of ammonium persulfate powder, and 100 mL of deionized water were weighed and stirred at room temperature for 50 min to obtain a mixed solution of sodium hydroxide and ammonium persulfate.

[0099] Next, a 2x2cm Cu-CFC was immersed in a mixture of sodium hydroxide and ammonium persulfate for 15 minutes to grow copper hydroxide nanoneedles, resulting in Cu(OH)2-CFC. The Cu-CFC was then rinsed repeatedly with deionized water.

[0100] 2. Assemble the Liquid Diode Evaporator

[0101] First, clean polystyrene foam was cut into a cylindrical shape with a diameter of 2.5 cm and a thickness of 0.5 cm. Five holes were then made in sequence on the surface of the cylinder. The pre-cut PF polyester cloth was inserted into the holes one by one, with the PF polyester cloth protruding 0.2 cm from the end surface of the polystyrene foam.

[0102] Then, Cu(OH)2-CFC was placed on the above-mentioned PF polyester cloth, wherein the side with Cu(OH)2 nanoneedles faced upward and the other side of the untreated polymer cloth faced downward and contacted the polyester cloth.

[0103] After the above steps, a liquid diode flexible evaporator of Cu(OH)2-CFC was obtained.

[0104] 3. Solar steam experiment

[0105] The evaporation rate of the liquid diode flexible evaporator obtained in this example under 1 sun is 1.91 kg m -2 h -1 .

[0106] Example 3

[0107] 1. Preparation of Cu(OH)2-CFC liquid diode flexible evaporator:

[0108] (1) Cleaning CFC substrate

[0109] In a numerically controlled ultrasonic cleaner with a frequency of 40 kHz, the polymer substrate of CFC was cleaned with deionized water and ethanol for 30 min and 30 min, respectively, and then placed in an oven for drying at a drying temperature of 45 °C to obtain a clean CFC substrate.

[0110] (2) Cu-CFC obtained by magnetron sputtering

[0111] The present invention adopts a dual-chamber reactive magnetron sputtering instrument to prepare samples, and uses a mechanical pump and a molecular pump to evacuate the chamber, and the vacuum degree can reach 10 -4 Pa, and is equipped with a corresponding water circulation system, bias plasma cleaning system, RF power supply, DC power supply, sample rotation stage, etc. During the sputtering process, the polymer substrate CFC substrate is placed on the upper sample stage. The polymer substrate CFC temperature is 25°C and the rotation speed is fixed at 9r / min. The sputtering target is installed at an angle to ensure that the entire substrate surface is coated. Ar can be introduced into the sputtering chamber.

[0112] The present invention sputters the Cu target under the condition of direct current power supply.

[0113] First, the vacuum degree of the sputtering chamber was pumped to a high vacuum of 1.8×10 -3 Pa, and then Ar was introduced as sputtering gas, and bombarded for 15 minutes in an Ar plasma atmosphere to remove impurities on the CFC film and improve the bonding strength between the coating and the polymer substrate, wherein the bias voltage was set to 450 V and the gas pressure was set to 5 Pa.

[0114] Then, the pressure in the vacuum chamber was adjusted to the required low vacuum pressure of 0.6 Pa for sputtering, and the sputtering power of the power supply was set to 100 W. Under this condition, the Cu target was pre-sputtered for 15 minutes to remove the oxide layer on the target surface and improve the purity of the deposit.

[0115] Finally, the shutter is opened, causing a glow discharge on the Cu target surface. The sputtered particles are then deposited onto the substrate surface under the action of an electric field. Specifically, the Cu target is sputtered for 45 minutes under a DC power supply to obtain a Cu layer of a certain thickness, resulting in a Cu coating of a certain thickness. The sputtering parameters for the Cu target include ensuring that the pressure in the vacuum chamber reaches the required high vacuum pressure of 0.6 Pa, setting the sputtering power of the power supply to 100 W, and starting the power supply.

[0116] Among them, the DC power supply conditions include: current 0.2A.

[0117] (3) Cu(OH)2-CFC nanoneedles grown at room temperature

[0118] First, the Cu-CFC obtained in step 2 above was cut into the required size (2*2 cm).

[0119] Next, 2.8 g of granular sodium hydroxide, 0.6 g of ammonium persulfate powder, and 100 mL of deionized water were weighed and stirred at room temperature for 40 minutes to obtain a mixed solution of sodium hydroxide and ammonium persulfate.

[0120] Then, a 2x2cm Cu-CFC was immersed in a mixture of sodium hydroxide and ammonium persulfate for 20 minutes to grow copper hydroxide nanoneedles, resulting in Cu(OH)2-CFC. The Cu-CFC was then rinsed repeatedly with deionized water.

[0121] 2. Assemble the Liquid Diode Evaporator

[0122] First, clean polystyrene foam was cut into a cylindrical shape with a diameter of 2.5 cm and a thickness of 0.5 cm. Five holes were then made in sequence on the surface of the cylinder. The pre-cut PF polyester cloth was inserted into the holes one by one, with the PF polyester cloth protruding 0.2 cm from the end surface of the polystyrene foam.

[0123] Then, Cu(OH)2-CFC was placed on the above-mentioned PF polyester cloth, wherein the side with Cu(OH)2 nanoneedles faced upward and the other side of the untreated polymer cloth faced downward and contacted the polyester cloth.

[0124] After the above steps, a liquid diode flexible evaporator of Cu(OH)2-CFC was obtained.

[0125] 3. Solar steam experiment

[0126] The evaporation rate of the liquid diode flexible evaporator obtained in this example under 1 sun is 2.14 kg m -2 h -1 .

[0127] Example 4

[0128] 1. Preparation of Cu(OH)2-CFC liquid diode flexible evaporator:

[0129] (1) Cleaning CFC substrate

[0130] In a numerically controlled ultrasonic cleaner with a frequency of 30 kHz, the polymer substrate of CFC was cleaned with deionized water and ethanol for 30 min and 30 min, respectively, and then placed in an oven for drying at a drying temperature of 50 °C to obtain a clean CFC substrate.

[0131] (2) Cu-CFC obtained by magnetron sputtering

[0132] The present invention adopts a dual-chamber reactive magnetron sputtering instrument to prepare samples, and uses a mechanical pump and a molecular pump to evacuate the chamber, and the vacuum degree can reach 10 -4Pa, and is equipped with a corresponding water circulation system, bias plasma cleaning system, RF power supply, DC power supply, sample rotation stage, etc. During the sputtering process, the polymer substrate CFC substrate is placed on the upper sample stage. The polymer substrate CFC temperature is 25°C and the rotation speed is fixed at 9r / min. The sputtering target is installed at an angle to ensure that the entire substrate surface is coated. Ar can be introduced into the sputtering chamber.

[0133] The present invention sputters the Cu target under the condition of direct current power supply.

[0134] First, the vacuum degree of the sputtering chamber was pumped to a high vacuum of 1.8×10 -3 Pa, and then Ar is introduced as sputtering gas, and bombarded for 10 minutes in an Ar plasma atmosphere to remove impurities on the CFC film and improve the bonding strength between the coating and the polymer substrate, wherein the bias voltage is set to 450V and the gas pressure is set to 5Pa.

[0135] Then, the pressure in the vacuum chamber was adjusted to the required low vacuum pressure of 0.6 Pa for sputtering, and the sputtering power of the power supply was set to 100 W. Under this condition, the Cu target was pre-sputtered for 20 minutes to remove the oxide layer on the target surface and improve the purity of the deposit.

[0136] Finally, the baffle is opened, causing a glow discharge on the Cu target surface. The sputtered particles are then deposited onto the substrate surface under the action of an electric field. Specifically, the Cu target is sputtered for 60 minutes under a DC power supply to obtain a Cu layer of a certain thickness, resulting in a Cu coating of a certain thickness. The sputtering parameters for the Cu target include setting the pressure in the vacuum chamber to the required high vacuum pressure of 0.6 Pa, setting the sputtering power of the power supply to 100 W, and starting the power supply.

[0137] Among them, the DC power supply conditions include: current 0.2A.

[0138] (3) Cu(OH)2-CFC nanoneedles grown at room temperature

[0139] First, the Cu-CFC obtained in step 2 above was cut into the required size (2*2 cm).

[0140] Next, 2.9 g of granular sodium hydroxide, 0.7 g of ammonium persulfate powder, and 100 mL of deionized water were weighed and stirred at room temperature for 45 minutes to obtain a mixed solution of sodium hydroxide and ammonium persulfate.

[0141] Then, a 2x2cm Cu-CFC was immersed in a mixture of sodium hydroxide and ammonium persulfate for 30 minutes to grow copper hydroxide nanoneedles, resulting in Cu(OH)2-CFC. The Cu-CFC was then rinsed repeatedly with deionized water.

[0142] 2. Assemble the Liquid Diode Evaporator

[0143] First, clean polystyrene foam was cut into a cylindrical shape with a diameter of 2.5 cm and a thickness of 0.5 cm. Five holes were then made in sequence on the surface of the cylinder. The pre-cut PF polyester cloth was inserted into the holes one by one, with the PF polyester cloth protruding 0.2 cm from the end surface of the polystyrene foam.

[0144] Then, Cu(OH)2-CFC was placed on the above-mentioned PF polyester cloth, wherein the side with Cu(OH)2 nanoneedles faced upward and the other side of the untreated polymer cloth faced downward and contacted the polyester cloth.

[0145] After the above steps, a liquid diode flexible evaporator of Cu(OH)2-CFC was obtained.

[0146] 3. Solar steam experiment

[0147] The evaporation rate of the liquid diode flexible evaporator obtained in this example under 1 sun is 1.86 kg m -2 h -1 .

[0148] The present invention will be further described below with reference to the accompanying drawings:

[0149] 1. SEM image test

[0150] like Figure 1 As shown in the middle figure (a~f), it can be seen from the SEM image that in the liquid diode flexible evaporator prepared in Example 3, Cu forms a coating in the form of nanorods on the surface of the carbon fiber cloth substrate, and Cu(OH)2 nanoneedles are densely stacked in the form of nanoneedles on the surface of the carbon fiber cloth substrate. Sunlight can be reflected multiple times in the space formed around the nanoneedles, further improving the light absorption performance.

[0151] 2. Solar Steam Experiment

[0152] A 3.5wt% saline solution was used to simulate seawater concentration, and a xenon lamp (CEL-HXF300, AM1.5 filter) was used to simulate sunlight. The mass change during evaporation was measured using an electronic microbalance (AR224CN) with an accuracy of 0.0001g and recorded using SPDC data acquisition V2.01 software on a personal computer (PC). A solar evaporation experimental platform was constructed. Analysis and calculations were performed to determine the evaporation rates of the carbon fiber cloth and liquid diode flexible evaporators under the experimental conditions, allowing for photothermal performance studies.

[0153] Pour an appropriate amount of 3.5 wt% salt water into a beaker, place the liquid diode evaporator into the salt water, and fix the sample so that it does not sink into the salt water. Place all the components on a precision electronic balance and monitor the mass change caused by water evaporation in real time. -2 ), to conduct solar steam generation tests.

[0154] The evaporation performance of the liquid diode flexible evaporator is determined by quantitative analysis through evaporation experiments.

[0155] The evaporation experiment was completed using an experimental device that simulated sunlight. All data were read by an electronic balance in a mass difference manner and then transferred to a computer for recording. Figure 2 As shown in the figure, the evaporation experiment found that the liquid diode flexible evaporator prepared in Example 3 had a thermal conductivity of 2.14 kg m - 2 h -1 The evaporation rate of pure CFC under natural sunlight is very slow. All evaporation experiments were carried out under 1 sun intensity.

[0156] 3. Contact angle test

[0157] like Figure 3 As shown, the contact angle of the front side (upper layer of the liquid evaporator) of the Cu(OH)2-CFC prepared in Example 3 of the present invention is about 0°, and the contact angle of the back side (lower layer of the liquid evaporator) of the Cu(OH)2-CFC is about 140°. Their different wettabilities ensure an excellent unidirectional water transport effect.

[0158] In summary, the present invention provides a flexible evaporator based on copper hydroxide liquid diode, a preparation method and its application in interfacial solar seawater evaporation. A Cu layer of a certain thickness (single side) is deposited on a carbon fiber cloth by magnetron sputtering using a Cu target, and Cu(OH)2 nanoneedles are grown at room temperature to make a Cu(OH)2-CFC flexible photothermal absorption material. PF polyester cloth and polystyrene foam are then used as support to assemble a liquid diode flexible evaporator for interfacial solar steam generation, thereby reducing heat loss and further improving evaporation efficiency and photothermal conversion efficiency.

[0159] The porous Cu(OH)2-CFC flexible photothermal absorber material has different wettabilities on its front and back surfaces. Positioning the hydrophilic surface on the upper layer and the hydrophobic surface on the lower layer, combined with the porous structure of the fiber cloth, ensures excellent one-way water transport in the liquid diode flexible evaporator, significantly reducing heat loss caused by water backflow and enabling efficient steam generation. Compared to traditional two-way water transport for seawater desalination, this invention innovatively proposes a new material and evaporator with one-way water transport, ensuring high absorption while maintaining low heat loss. This is expected to provide a new strategy for the preparation of solar interfacial steam generation systems and achieve efficient seawater desalination.

[0160] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a liquid diode flexible evaporator based on copper hydroxide, characterized in that: The following steps are involved: S1: using Ar as a sputtering gas to remove impurities on the polymer substrate to obtain a clean polymer substrate; performing a pre-sputtering treatment on a Cu target to obtain a Cu target with a surface oxide layer removed; in S1, the polymer substrate is a carbon fiber cloth; S2: On a clean polymer substrate, a Cu target is sputtered under DC power supply conditions to prepare a single-sided copper-plated polymer material; S3: Immersing a single-sided copper-plated polymer material in a mixed solution of sodium hydroxide and ammonium persulfate to obtain a liquid diode photothermal absorption material having copper hydroxide nanoneedles grown on one side; in S3, the mass ratio of sodium hydroxide to ammonium persulfate in the mixed solution is (2.6-2.9): (0.4-0.7); S4: cleaning the liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side to a set pH value and then spreading the material flat on a support, so that the side of the liquid diode photothermal absorption material with copper hydroxide nanoneedles grown on one side without copper hydroxide nanoneedles growing thereon contacts the support, thereby obtaining a liquid diode flexible evaporator; in S4, the liquid diode flexible evaporator further comprises a support base, the support body is disposed on the support base, and the support base is polystyrene foam; The prepared material consists of hydrophilic copper hydroxide nanoneedles on one side and a superhydrophobic polymer on the other, with the two sides exhibiting different wettabilities. Liquid diode flexible evaporator with one-way water transport function.

2. The method for preparing a liquid diode flexible evaporator based on copper hydroxide according to claim 1, characterized in that: In S1, the process of using Ar as a sputtering gas to remove impurities on the polymer substrate and obtain a clean polymer substrate is as follows: At a first set vacuum degree, Ar is introduced as a sputtering gas, and the sputtering is carried out in an Ar plasma atmosphere for a first set time; wherein the first set vacuum degree is 1.8×10 -3 Pa or less; the first setting time is 10~20 min; the bias voltage during the bombardment process is 450 V and the gas pressure is 5 Pa.

3. The method for preparing a liquid diode flexible evaporator based on copper hydroxide according to claim 1, characterized in that: In S1, the process of performing pre-sputtering treatment on the Cu target to obtain a Cu target with the oxide layer on the surface of the target material removed is as follows: Under the second set vacuum degree, the sputtering power value is set and then the sputtering is performed for the second set time; the second set vacuum degree is 0.6 Pa, the sputtering power value is 100 W, and the second set time is 10 to 20 minutes.

4. The method for preparing a liquid diode flexible evaporator based on copper hydroxide according to claim 1, characterized in that: In S2, the process parameters of the DC power supply condition are as follows: the current of the DC power supply condition is 0.2A; the sputtering time is 15-60 min; the sputtering vacuum is 0.6 Pa; and the sputtering power value is 100W.

5. The method for preparing a liquid diode flexible evaporator based on copper hydroxide according to claim 1, characterized in that: In S4, the cleaning is performed with deionized water; the set pH value is 7; and the support is PF polyester cloth.

6. A liquid diode flexible evaporator prepared according to the method for preparing a liquid diode flexible evaporator based on copper hydroxide according to any one of claims 1 to 5, characterized in that: The water in the liquid diode flexible evaporator can be transported upward from the lower hydrophobic layer to the upper hydrophilic layer; In the liquid diode flexible evaporator, Cu forms a coating in the form of nanorods on the surface of the carbon fiber cloth substrate, and Cu(OH)2 nanoneedles are densely stacked in the form of nanoneedles on the surface of the carbon fiber cloth substrate.

7. Use of the liquid diode flexible evaporator according to claim 6 in seawater desalination.

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