CN111041451A

CN111041451A - Durable anti-icing surface modification material and preparation method thereof

Info

Publication number: CN111041451A
Application number: CN201911396114.1A
Authority: CN
Inventors: 王鹏飞; 曹莹泽; 卢亚妹; 戴春爱
Original assignee: China Academy of Space Technology CAST
Current assignee: China Academy of Space Technology CAST
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-04-21

Abstract

The invention provides a preparation method of a durable anti-icing surface modification material, which comprises the following steps: (1) carrying out surface modification on the substrate, and uniformly depositing a carbon layer on the surface of the substrate; (2) respectively placing ethyl orthosilicate and ammonia water in an open container; (3) placing the substrate subjected to surface modification in the step (1) and the open container in the step (2) in a room-temperature closed state for vapor deposition; (4) annealing the substrate material treated in the step (3); (5) and performing secondary surface modification on the annealed substrate material, and placing the annealed substrate material and an open container filled with fluorosilane in a room-temperature vacuum state for vapor deposition. The method solves the technical problems that the preparation method of the super-hydrophobic material in the prior art is complex, high in cost, stable in structure, and has to be improved in corrosion resistance and friction resistance.

Description

Durable anti-icing surface modification material and preparation method thereof

Technical Field

The invention belongs to the technical field of super-hydrophobic surface preparation, and particularly relates to a durable anti-icing surface modification material and a preparation method thereof.

Background

Super-hydrophobicity is a special wettability, generally meaning that a water drop is spherical on a solid surface, the contact angle is more than 150 degrees, and the rolling angle is less than 10 degrees. The lower the surface energy (the energy of the material surface molecules is more than that of the internal molecules), the better the hydrophobicity is, and when the low-surface-energy material has a micro-rough structure, an air film can be formed between water drops and the material to prevent the water from wetting the surface of the material, so that a super-hydrophobic state is formed.

The initial inspiration of superhydrophobic surfaces comes from the "lotus leaf effect". In the 90 s of the 20 th century, Barthlott, a Bonn university of German botanicals, and the like, disclosed the structure of the lotus leaf surface, and found that the self-cleaning property of the lotus leaf comes from the micro-nano structure of the lotus leaf surface, the lotus leaf surface is provided with micron-sized papilla, and the papilla is provided with nano-scale wax crystal substances, and the micro-nano coarse structure can greatly improve the contact angle of water drops on the lotus leaf surface, so that the water drops are easy to roll off.

Because the water drops can take away the pollutants when rolling off on the surface of the super-hydrophobic material, the surface of the material is kept clean. Therefore, the super-hydrophobic material has multiple characteristics of water resistance, corrosion resistance, ice resistance, adhesion resistance and the like.

Ice formation and accumulation are common in all aspects, and icing and frosting bring inconvenience to daily life and industrial production of people, and ice accumulation on a power transmission line seriously threatens safe operation of power, railways, telecommunication systems and networks; ice formation and deposition also pose serious economic and safety problems for many infrastructure (e.g., aircraft, ships, etc.) as well as many commercial sites and residences; frost covers the leaves of outdoor plants causing loss of plant cell activity, resulting in plant death and agricultural loss. In the prior art, many conventional methods have been used to prevent ice formation and accumulation, such as chemical de-icing, mechanical vibration, steam heating and electrical heating, which have some effects, but have the disadvantages of low efficiency, high energy consumption, high risk, environmental pollution, etc.

Unlike the traditional active deicing method, the passive deicing method is more and more concerned by the outside world due to the characteristic of zero energy consumption. Theoretically, ice formation is the typical phase change process from supercooled liquid water to ice, hydrophilic materials are subject to water adhesion, and water droplets tend to form ice on this type of solid surface. Most engineered materials, however, are hydrophilic, and therefore, the key to preventing ice formation and ice accretion is to impart to the solid surface the ability to resist water droplet adhesion and repel water and ice.

With the continuous research of people on the super-hydrophobic material, at present, the super-hydrophobic surface prepared by methods such as a vapor deposition method, a sol-gel method, an etching method, a template method and the like has made a certain progress in the anti-icing field.

For example, chinese patent No. 201710263591.5 entitled "method for preparing superhydrophobic coating capable of enduring anti-icing" discloses a method for preparing superhydrophobic coating capable of enduring anti-icing, which specifically includes the following steps: step 1, cleaning and sandblasting coarsening treatment is carried out on the surface of a base material; step 2, blending the epoxy resin, the curing agent and the first solvent to obtain an epoxy resin solution; step 3, dispersing the submicron particles and the nanoparticles in a second solvent, and adding a silane coupling agent to obtain a particle composite suspension; step 4, spraying the epoxy resin solution obtained in the step 2 on the surface of the substrate treated in the step 1, and semi-curing the epoxy resin adhesive; step 5, spraying the particle composite suspension obtained in the step 3 on the surface of the base material obtained in the step 4, and completely curing; and 6, obtaining the durable anti-icing super-hydrophobic coating. The test result of the technical scheme of the invention shows the anti-icing effect when the temperature is below-10 ℃, but if the temperature is below-10 ℃, the anti-icing effect is not seen.

In addition, a Chinese patent with application number 201710093399.6 and named as a preparation method of a super-hydrophobic coating discloses a preparation method of the super-hydrophobic coating suitable for various substrates, and specifically, tetraethoxysilane is added into a mixed solution of ammonia water and absolute ethyl alcohol and stirred for 1-2 hours, then a tannic acid solution is slowly added and stirred for 30-60 min, HMDS is added and stirred for 30-60 min, the stock solution is sprayed onto different base materials, and the super-hydrophobic coating is obtained after drying. The technical scheme of the invention is suitable for various substrates, but the anti-icing effect at low temperature is not shown.

Disclosure of Invention

The invention aims to provide a durable anti-icing surface modification material and a preparation method thereof, and solves the technical problems that the preparation method of the durable anti-icing surface modification material in the prior art is complex, high in cost, limited in low-temperature resistance, and improved in structural stability, corrosion resistance and friction resistance.

The technical scheme of the invention is as follows: a method for preparing a durable anti-icing surface modification material comprises the following steps:

(1) carrying out surface modification on the substrate, and uniformly depositing a carbon layer on the surface of the substrate;

(2) respectively placing ethyl orthosilicate and ammonia water into two open bottles;

(3) putting the substrate with the surface modified in the step (1) and the open bottle filled with the solution in the step (2) together in a room-temperature closed state for vapor deposition;

(4) annealing the substrate material treated in the step (3);

(5) and performing secondary surface modification on the annealed substrate material, and performing vapor deposition on the annealed substrate material and an open bottle filled with fluorosilane at room temperature under vacuum to obtain the super-hydrophobic material.

Preferably, the substrate is subjected to surface cleaning before surface modification, including ultrasonic cleaning and drying of the substrate surface with deionized water and ethanol.

Preferably, in the step (2), a carbon layer is deposited on the surface of the substrate by using the candle, the deposition time is 5-30s, and the thickness of the carbon layer is 15-50 μm.

Preferably, the gas phase deposition time in the step (3) is 24 h.

Preferably, the annealing temperature in the step (4) is 450-600 ℃, and the annealing time is 2 h.

Preferably, the gas phase deposition time in the step (5) is 72-144 h.

Preferably, the side length of the substrate in the step (1) is 2-10 cm; the volumes of the ethyl orthosilicate and the ammonia water are respectively 2-7 mL; the volume of the fluorosilane in the step (5) is 0.3-1 mL.

Preferably, the substrate is a stainless steel plate, an aluminum plate, or quartz glass.

The other technical scheme of the invention is as follows: a durable anti-icing surface finishing material is prepared by the preparation method.

The other technical scheme of the invention is as follows: the durable anti-icing surface finishing material is applied to the anti-icing field, and is used for wires hung at high altitude outdoors, airplane wings and impellers of wind driven generators.

The preparation method of the durable anti-icing surface modification material provided by the invention is easy to operate, low in preparation cost and capable of being prepared in a large scale. The prepared durable anti-icing surface modification material has a high contact angle and an extremely low adhesion force, water drops can roll off or rebound on the surface very easily, and the adhesion and aggregation of the water drops on the surface are effectively prevented. And the water drops take away the surface scraps and dust in the rolling process, so that the surface self-cleaning effect is achieved. In an anti-icing experiment, the material has a remarkable anti-icing effect, and effectively delays the conversion of water drops to ice at a low temperature of 18 ℃ below zero. Due to the extremely low adhesion force of the surface, even if the surface is frozen, ice can roll off from the surface easily under the action of perturbation, and the ice-resistant and ice-removing ice cream has good anti-icing and ice-removing effects. Meanwhile, the material has stable surface structure performance, and still has excellent anti-icing performance after repeated icing/deicing. In addition, the material can resist corrosion and friction, is easy to store, and provides a new idea and method for effectively resisting and removing ice on the surface of the material.

Drawings

FIG. 1 is a scanning electron microscope photograph of the surface morphology of the durable anti-icing surface modification material prepared in example 1 of the present invention;

FIG. 2a is a photograph of the contact angle of a water drop on the surface of the durable anti-icing surface modification material prepared in example 1 of the present invention;

FIG. 2b is a photograph of the contact angle of a water drop on the surface of a comparative example material without surface modification;

FIG. 3 is a graph of the surface cycle anti-icing performance of the durable anti-icing surface modification material prepared in example 1 of the present invention;

FIG. 4a is a graph showing the corrosion resistance effect of the surface of the durable anti-icing surface modification material prepared in example 1 of the present invention in HCl solution;

FIG. 4b is a graph showing the corrosion resistance effect of the surface of the durable anti-icing surface modification material prepared in example 1 of the present invention in a NaCl solution.

Detailed Description

The present invention will be described in further detail with reference to examples, but the scope of the present invention is not limited to these examples. In the following examples, all materials and reagents are not particularly limited in source and are commercially available, and tetraethoxysilane, ammonia water and fluorosilane used in the present invention are all commercially available analytical reagents.

The preparation method of the durable anti-icing surface modification material comprises the following steps:

(1) treatment of the substrate: selecting a stainless steel plate, an aluminum plate and quartz glass with proper shapes, ultrasonically cleaning and drying deionized water and ethanol for later use, and preferably selecting a substrate with the side length of 2-10 cm;

(2) surface modification: uniformly depositing a carbon layer with a certain thickness on the surface of the substrate by using a candle, wherein the deposition time is 5-30s, preferably 15s, and the roughness and the porous structure of the surface of the substrate are increased;

(3) putting the substrate in the step (2) into a dryer, simultaneously adding an open glass container filled with a certain volume of tetraethoxysilane and ammonia water respectively, and depositing for a period of time at room temperature in a closed state, wherein the volume of tetraethoxysilane and the volume of ammonia water are 2-7 mL, preferably 4mL respectively, and the vapor deposition time is 24 hours;

(4) putting the material in the step (3) into a muffle furnace, annealing at a certain temperature, and taking out, wherein the annealing temperature is 450-600 ℃, and the annealing time is 2 hours, so that redundant substances are removed, and only silicon dioxide is left;

(5) secondary surface modification: putting the material obtained in the step (4) into a dryer, and simultaneously putting an open space filled with fluorosilane with a certain volumeDepositing in a glass container at room temperature under vacuum for a period of time, taking out to obtain the super-hydrophobic material, and storing for later use, wherein the relation between the quantity of the fluorosilane and the area of the substrate is more than 0.05mL/cm²Preferably, the volume is 0.3-1mL, further preferably 0.5mL, and the vapor deposition time is 72-144h, preferably 96-120 h; the deposition of fluorosilane reduces the surface energy of the substrate material, resulting in a hydrophobic low adhesion surface.

The contact angle of the durable anti-icing surface modification material prepared by the invention and water is more than 150 degrees, and the water drop has extremely low adhesion with the surface, so that the water drop can rebound and roll off quickly on the surface, and the adhesion and aggregation of the water drop on the surface are effectively prevented. The water drops can also take away the scraps and dust on the surface in the process of rolling off the surface, thereby achieving the self-cleaning effect. In an anti-icing test of the material, the surface of the durable anti-icing surface modified material has obvious anti-icing performance, compared with an unmodified surface, due to the fact that the micro/nano structure exists on the surface of the material prepared by the method, contact between a water drop and the surface is point contact, heat conduction between the water drop and an air layer on the surface is effectively blocked, and therefore conversion from the water drop to ice is effectively delayed. With the reduction of the temperature, the surface anti-icing effect of the durable anti-icing surface modification material is still obvious, the anti-icing material can rapidly remove ice under the action of perturbation, and the anti-icing/deicing at low temperature is realized. In a cyclic icing/deicing experiment, after repeated icing/deicing, the surface of the super-hydrophobic material still has excellent anti-icing performance, and has an obvious icing delaying effect, and the super-hydrophobic material has good durability. In addition, through soaking in acid, alkali and salt solutions, the contact angle of water drops on the surface of the durable anti-icing surface modification material can still be stabilized above 150 degrees, and the anti-icing effect is not obviously reduced, which shows that the surface of the durable anti-icing surface modification material has the corrosion resistance. Due to the good characteristics of the surface of the durable anti-icing surface finishing material, a new idea and a new method are provided for the prior anti-icing and deicing fields, and the durable anti-icing surface finishing material can be applied to the surfaces of wires hung at high altitude outdoors, airplane wings, impellers of wind driven generators and the like.

Example 1

The present embodiment provides a durable anti-icing surface modification material, which is prepared by the following steps:

(1) selecting a rectangular stainless steel plate with the specification of 2 multiplied by 5cm, and cleaning and drying the stainless steel plate for later use;

(2) uniformly depositing carbon on the surface of the stainless steel by using a candle for 20 s;

(3) putting the stainless steel plate obtained in the step (2) into a dryer, and simultaneously putting the stainless steel plate into open glass containers respectively filled with tetraethoxysilane and ammonia water, wherein the volumes of the two solutions are 4 mL;

(4) in the step (3), the tetraethoxysilane and ammonia water are subjected to sealed deposition reaction at room temperature for 24 hours;

(5) taking out the material in the step (4), and putting the material into a muffle furnace for annealing at the annealing temperature of 600 ℃ for 2 h;

(6) taking out the material in the step (5), putting the material into a dryer, and simultaneously putting the material into an open glass container containing fluorosilane, wherein the volume of the fluorosilane is 0.5 mL;

(7) and (6) performing vacuum deposition on fluorosilane at room temperature for 96 hours to obtain the durable anti-icing surface modification material.

Referring to fig. 1, the surface morphology of the durable anti-icing surface modification material prepared in this embodiment under an electron microscope is shown. The contact angle of the durable anti-icing surface modification material prepared by the embodiment to water in the air is up to 160 degrees.

In order to fully know the performance of the surface of the prepared material, the unmodified surface is used as a reference, and tests of super hydrophobicity, self-cleaning, surface water drop rebound, icing time delay and corrosion resistance are carried out, wherein the specific test processes are as follows:

(1) hydrophobic Performance test

On the surface of the material of this example and the surface of the comparative example (stainless steel plate without any treatment), water droplets were dropped, and it was observed that: the water drops are not unfolded on the surface of the modified super-hydrophobic material and are in a spherical shape, the contact angle of the water drops is about 160 degrees, and the water drops are easy to roll or slide off, and see fig. 2 a; in contrast, the drop was almost completely wetted on the unmodified control surface, the drop contact angle was about 90 °, see fig. 2 b.

(2) Self-cleaning test

The surface of the super-material of the embodiment and the surface of the reference example are respectively inclined at a certain angle, wood waste is sprinkled on the two surfaces, liquid drops are continuously dripped on the two surfaces, and the observation shows that: the water drops roll off on the surface of the super-hydrophobic material and simultaneously take away the surface scraps; in contrast, the droplets wet and stick to the comparative example surface without carrying away surface debris.

(3) Surface water drop rebound test

The surface of the material of the embodiment and the surface of the comparison example are placed on a platform, liquid drops are vertically dripped at a position 10-20cm above the surface, the rebound process of the water drops is shot by a high-speed camera, and the observation shows that: water drops can rebound rapidly on the surface of the super-hydrophobic material; in contrast, the water droplets wet on the comparative example surface and no rebound occurred.

(4) Icing delay test

Placing the surface of the material of the embodiment and the surface of the comparison example on a cold table, adjusting the temperature of the cold table to be-3 ℃ to-18 ℃ and the temperature interval to be 3 ℃, dripping water drops on the two surfaces, simultaneously recording the time of starting freezing and completely freezing of the water drops, and observing and finding: the water drops on the surface of the unmodified comparative example are almost wet, and the water drops are frozen in about 60 s; in contrast, the water drops on the surface of the superhydrophobic material still show a spherical shape, and the icing time is prolonged to 300s to 400s, as shown in fig. 3.

(5) Corrosion resistance test

The surface of the material of this example was soaked in 0.05M HCl and 0.05M NaCl solutions for 1 hour, wherein the change of the contact angle of the surface water drop was measured at 10min intervals, and observed to find: the contact angle of the surface water drop does not change significantly due to the soaking of the solution, and the contact angle of the water drop is still stable above 150 degrees, see fig. 4a and 4 b.

Example 2

(1) selecting a square aluminum plate with the specification of 5 multiplied by 5cm, and cleaning and drying the square aluminum plate for later use;

(2) uniformly depositing carbon on the surface of the stainless steel by using a candle, wherein the deposition time is 25 s;

(3) putting the stainless steel plate obtained in the step (2) into a dryer, and simultaneously putting the stainless steel plate into open glass containers respectively filled with tetraethoxysilane and ammonia water, wherein the volumes of the two solutions are 3 mL;

(6) taking out the material in the step (5), putting the material into a dryer, and simultaneously putting the material into an open glass container containing fluorosilane, wherein the volume of the fluorosilane is 0.6 mL;

(7) and (6) performing vacuum deposition on fluorosilane at room temperature for 120h to obtain the durable anti-icing surface modification material.

The contact angle of the material prepared in the embodiment to water in air is more than 150 degrees.

Example 3

(1) selecting rectangular quartz glass with the specification of 2 multiplied by 5cm, and cleaning and drying the quartz glass for later use;

(6) taking out the material in the step (5), putting the material into a dryer, and simultaneously putting the material into an open glass container containing fluorosilane, wherein the volume of the fluorosilane is 0.7 mL;

(7) and (6) performing vacuum deposition on fluorosilane at room temperature for 144h to obtain the durable anti-icing surface modification material.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a durable anti-icing surface modification material is characterized by comprising the following steps:

(4) annealing the substrate material treated in the step (3);

2. The method of claim 1, wherein the surface cleaning of the substrate before the surface modification of the substrate comprises ultrasonic cleaning and drying of the substrate surface with deionized water and ethanol.

3. The method as claimed in claim 1, wherein in the step (2), the candle is used to deposit the carbon layer on the surface of the substrate, the deposition time is 5-30s, and the thickness of the carbon layer is 15-50 μm.

4. The production method according to claim 1, wherein the vapor deposition time in the step (3) is 24 hours.

5. The method as claimed in claim 1, wherein the annealing temperature in step (4) is 450-600 ℃, and the annealing time is 2 h.

6. The production method according to claim 1, wherein the vapor deposition time in the step (5) is 72 to 144 hours.

7. The production method according to claim 1, wherein the substrate side in the step (1) is 2 to 10 cm; the volumes of the ethyl orthosilicate and the ammonia water are respectively 2-7 mL; the volume of the fluorosilane in the step (5) is 0.3-1 mL.

8. The method according to any one of claims 1 to 7, wherein the substrate is a stainless steel plate, a stainless steel wire, an aluminum plate, or quartz glass.

9. A durable anti-icing surface modification material, characterized by being produced by the production method according to any one of claims 1 to 8.

10. Use of the durable anti-icing surface modification material of claim 9 in the anti-icing field for outdoor overhead suspended electrical wires, aircraft wings and wind turbine blades.