Super-lubricating organic gel coating with self-adaptability and wear resistance and preparation method of super-lubricating organic gel coating

A kind of self-adaptive, wear-resistant super-lubricating organic gel coating and its preparation method Technical field

[0001] The invention belongs to the technical field of organic gel coatings, in particular to a super-lubricating organic gel coating with self-adaptability and wear resistance and a preparation method thereof.

Background technique

The superlubricating material (slippery surface) of imitation pitcher plant structure is a class of solid-liquid composite structure interface material (Nature, 2011,477,443-447) that rises in recent years, by water/oily lubricant perfusion to nano / micron-structured rough substrate, forming a stable and inert smooth surface. The surface has good liquid repellency, ice resistance, pressure stability and other characteristics. In actual use, when the super-lubricated surface is subjected to external mechanical wear, the lubricating fluid on the surface will gradually lose, resulting in a decrease in its wettability, and may seriously shorten its service life. Therefore, when preparing superlubricating materials, it is necessary to focus on the wear resistance of the material, but the current lubricating materials often do not have anti-wear properties. The sol-gel method is used to prepare rough substrates, and then modified with low surface energy substances and covered with lubricating oil to obtain super lubricating materials. Most of the surfaces of these superlubricating materials will fail due to friction loss of lubricating oil, which will greatly limit the application range of superlubricating materials. Therefore, it is an urgent problem to be solved at present to prepare super-lubricating materials with wear-resistant imitation pitcher plant structures.

Contents of the invention

Summary of the invention For the technical problem that the lubricity of superlubricating material reduces with wear and tear in the prior art, the invention provides a kind of superlubricating organogel coating and preparation method thereof with self-adaptability, wear resistance, this organogel The coating can intelligently regulate the lubricating properties of the surface of the material, and can self-adaptively resist water or oil, which is conducive to the use of super-lubricating materials in complex environments and expands their application range.

The technical scheme that the present invention solves the problems of the technologies described above is as follows:

[0005] The preparation method of the present invention's self-adaptive, wear-resistant super-lubricating organic gel coating, the steps are as follows: [0006] Step 1, dopamine is dissolved in water, adjust pH=7.5 ~ 9.0, the solution becomes After becoming brownish black, apply it on the pretreated substrate, react at 15~35°C for 15~24h, rinse, and dry at room temperature to obtain the polydopamine substrate;

Step 2, the polydimethylsiloxane (MA-PDMS) solution that methacrylate is modified is sprayed on the polydopamine substrate, photopolymerizes 30s under UV lamp (365nm), obtains methacrylate modification Polydimethylsiloxane (MA-PDMS) membrane;

Step 3, under the lubricating oil fusing point temperature higher than the liquid-solid phase transition that can occur, the lubricating oil that can occur liquid-solid phase transition is mixed with the lipid vesicle of embedding glycerol to obtain coating solution, and The coating solution is coated on the methacrylate modified polydimethylsiloxane film to obtain an adaptive and wear-resistant super-lubricating organogel coating.

Preferably, in described step one, after dopamine is dissolved in water, the amount of substance of dopamine is 1wt%.

Preferably, in described step one, cooperate hydrochloric acid solution to regulate pH=7.5~9.0 with tris buffer solution (Tris-HCl), sodium hydroxide solution, borax buffer solution or ammonia solution.

[0011] Preferably, in the step one, the pretreatment process of the substrate is: the substrate is successively ultrasonically cleaned with acetone, ethanol, and water for 10min, and nitrogen is blown dry for subsequent use.

[0012] Preferably, in the step one, the substrate is metal, ceramics, plastics or glass.

[0013] Preferably, in the step one, the method used for coating is spin coating, spray coating or dip coating.

Preferably, in described step 2, the polydimethylsiloxane (MA-PDMS) solution concentration range 1~5mg/mL that methacrylate modifies.

Preferably, in described step 2, the preparation method of the polydimethylsiloxane (MA-PDMS) solution that methacrylate modifies is: the hydroxyl-terminated polydimethylsiloxane (PDMS) , silane coupling agent, catalyst dibutyltin dilaurate (DTBL) and deionized water (H2O) were stirred and mixed evenly at room temperature, and the obtained mixed solution was placed in an oven, dehydrated under reduced pressure at 60 ° C, and then added photoinitiator 1173 (HMPP), stirred evenly at room temperature to obtain a methacrylate-modified polydimethylsiloxane (MA-PDMS) solution.

More preferably, the hydroxyl-terminated polydimethylsiloxane molecular weight is 10k, 20k or 50k;

Silane coupling agent is KH570 or KH571;

Hydroxy-terminated polydimethylsiloxane (PDMS), silane coupling agent, catalyst dibutyltin laurate (DTBL) and deionized water (H₂O) the mol ratio is 1: (35~40): (1~2): (125-130);

The massfraction of photoinitiator 1173 is 3%~5%;

Stirring adopts magnetic stirrer, and stirring velocity is 1000r/min, and stirring time is 12h.

Preferably, in described step 2, the distance between substrate and UV lamp is set to 10~15cm.

Preferably, in described step 3, the preparation method of the lipid vesicle of embedding glycerol is: natural lipid is dissolved with chloroform, 37 °C of decompression rotary evaporations become uniform lipid film, then add glycerol, Hydrate at 60°C, in an ice bath, and sonicate the probe several times to obtain glycerol-embedded lipid vesicles.

More preferably, described natural lipid is 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1-palmitoyl-2-oleoyl-glycero-3-phosphate Choline (POPC) or 1,2-1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC); The proportioning of natural lipid, chloroform and glycerol is (40~80 ) mg: (2~4) mL: (1~3) mL;

Rotary evaporation time is 1~2h;

Hydration time is 40-801^3

Probe ultrasonic 5 times, the power of probe is 50W, each work 2s of probe ultrasonic response, suspend 2s.

Preferably, in described step 3, the lubricating oil that can take place phase transition is coconut oil (melting point: 23 °C), palm oil (melting point: 40 °C) or cottonseed oil (melting point: 5-10 °C).

[0029] Preferably, in step 3, the volume ratio of the lubricating oil that can undergo phase transition to the lipid vesicles embedding glycerol is 1:9, 2:8 or 3:7.

Preferably, in described step 3, the method that coating adopts is spin coating, spray coating or dip coating, and the dip coating time is 5h, and the condition of spraying process is: adopt compressed air spraying, spraying pressure 1.1~10bar; Spray liquid flow rate: 150110001^/min.

[0031] The present invention also provides the self-adaptive, wear-resistant super-lubricating organic gel coating prepared by the preparation method of the above-mentioned self-adaptive, wear-resistant super-lubricating organic gel coating.

Principle of the present invention: the present invention has self-adaptability, the ultra-lubricating organogel coating of abrasion resistance, first on substrate, polydopamine is grafted, utilizes its strong adhesiveness to strengthen coating and substrate force between. Then, using the green water solvent method, the hydroxyl-terminated PDMS is modified by a silane coupling agent to covalently graft a photosensitive group (C = C), through

The PDMS network structure is obtained by UV irradiation-induced polymerization. At the same time, the high melting point lubricating oil is transformed from liquid to solid at low temperature, which can reduce the loss of liquid lubricant due to the influence of the external environment and prolong the service life of the coating. At the same time, in order to reduce the wear of the solid lubricant by the external environment and overcome the shortcomings of the solid lubricant's poor lubricity, the lipid vesicles embedding the glycerin of the water-based lubricant and the lubricating oil were embedded in the lubricating oil at a temperature higher than the melting point of the lubricating oil In the cross-linked network of PDMS, the PDMS network swells rapidly at this time. When the temperature decreases, on the one hand, the swelling rate of the PDMS network decreases; on the other hand, when the lubricating oil changes from liquid phase to solid phase, volume expansion occurs, causing The stress release of the elastic organogel allows the lubricant oil and lipid vesicles in the reservoir to secrete to the surface. When the surface is subjected to external impact or mechanical damage, the rupture of the lipid film will promote the water-based lubrication embedded in the vesicles. Glycerin, the agent, is released, and the glycerin will quickly fill and cover the defects caused by the wear of solid lubricating oil through diffusion, forming a super lubricating material with a solid-liquid composite structure, thereby achieving liquid lubrication performance. Compared with the existing slippery surface, this method greatly enhances the friction resistance of the lubricating material without losing the interfacial lubricity due to the existence of the cross-linked network and the embedded vesicles, effectively prolonging the lubricity. service life of the coating.

Compared with prior art, the beneficial effect of the present invention is:

[0034] The super-lubricating organic gel coating of the present invention has strong adhesion to the substrate and is difficult to peel off.

[0035] The super-lubricating organic gel coating of the present invention has self-adaptability, and does not lose interfacial lubricity while greatly enhancing the friction resistance of the lubricating material, effectively prolonging the service life of the lubricating coating.

[0036] The preparation method of the super-lubricating organic gel coating of the present invention is simple, easy to operate, and suitable for large-scale production.

Description of drawings

In order to more clearly illustrate the technical scheme in the embodiment of the present invention, the accompanying drawings that need to be used in the embodiment will be briefly introduced below, obviously, the accompanying drawings in the following description are only some implementations of the present invention For example, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the preparation flow diagram of the superlubricating organic gel coating that the present invention has self-adaptability, wear resistance.

In Fig. 2, A, B are respectively the water contact angle figure and the sliding angle figure that are coated with the glass of super-lubricating organic gel coat in embodiment 2 without sand friction surface;

C, D are the n-hexane contact angle figure and sliding angle figure that the glass that is coated with super-lubricating organogel coating in embodiment 2 is through sand rotation rubbing 20 times respectively.

Fig. 3 is that the glass that will be coated with super-lubricating organogel coating in embodiment 2 rotates and rubs 20 times in the physical figure in sand.

Detailed ways

[0042] In order to further understand the present invention, the preferred embodiments of the present invention are described below, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0043] As shown in Figure 1, the present invention has self-adaptive, wear-resistant super-lubricating organic gel coating, the steps are as follows: [0044] Step 1, dopamine is dissolved in water, adjust pH = 7.5 ~ 9.0 , after the solution turns brownish black (usually around 20min), apply it on the pretreated substrate, react at 15~35°C for 15~24h, rinse, and dry at room temperature to obtain the polydopamine substrate;

Step 2, PDMS, silane coupling agent, catalyst DTBL and deionized water are stirred and mixed evenly at room temperature, the mixed solution obtained is placed in oven, 60 °C of dehydration under reduced pressure, then add photoinitiator 1173, in Stir well at room temperature to obtain

to MA-PDMS solution;

Step 3, spray the MA-PDMS solution that step 2 obtains on the polydopamine substrate that step 1 obtains, photopolymerize 30s under UV lamp, obtain MA-PDMS film;

Step 4, natural lipid is dissolved with chloroform, and 37 °C of decompression rotary evaporations become uniform lipid film, then add glycerol, hydration under 60 °C of conditions, under ice bath, probe ultrasonic multiple times, obtain the embedding glycerin Lipid vesicles;

Step 5, under the lubricating oil fusing point temperature higher than the liquid-solid phase transition that can occur, the lubricating oil that can occur liquid-solid phase transition is mixed with the lipid vesicle of embedding glycerol to obtain coating solution, and The coating solution is coated on the methacrylate modified polydimethylsiloxane film to obtain an adaptive and wear-resistant super-lubricating organogel coating.

Above-mentioned technical scheme, in step one, configuration fresh alkaline dopamine aqueous solution, again this dopamine aqueous solution is coated on the substrate of pretreatment, dopamine and water polymerize on substrate surface, generate polydopamine. The reaction formula of polydopamine synthesis is as follows (N=10~10⁵)：

<img file="CN115382741A_D0001.tif" />

HO OH HO OH.

Above-mentioned technical scheme, in step one, after preferred dopamine is dissolved in water, the amount of the substance of dopamine is 1wt%; Preferably dopamine and the polydopamine that do not have firm combination on substrate surface with a large amount of steam storage water rinsing. The pretreatment process of the substrate is as follows: The substrate is ultrasonically cleaned with acetone, ethanol, and water for 10 minutes respectively, and dried with nitrogen gas for later use. The substrate is preferably metal, ceramic, plastic or glass. Preferably use Tris buffer solution (Tris-HCl), sodium hydroxide solution, borax buffer solution or ammonia solution to coordinate hydrochloric acid solution to adjust pH=7.5~9.0. The method used for coating is preferably spin coating, spray coating or dip coating.

Above-mentioned technical scheme, in step 2, the polydimethylsiloxane (MA-PDMS) solution of methacrylate modification prepares reference method (Angew.Chem.Int.Ed.2019,58,1-6 )conduct. Its reaction process is as follows:

<img file="CN115382741A_D0002.tif" />

PDMS KH571 MA-PDMS MA-PDMS membrane

Above-mentioned technical scheme, in step 2, molecular weight of hydroxyl-terminated polydimethylsiloxane is preferably 10k, 20k or 50k; Silane coupling agent is preferably KH570 or KH571: [0055] KH570 structural formula:

[0056]

<img file="CN115382741A_D0003.tif" />

KH571 structural formula:

<img file="CN115382741A_D0004.tif" />

The mol ratio of PDMS, silane coupling agent, catalyst DTBL and deionized water is preferably 1: (35~40): (1~2): (125~130); The massfraction of the photoinitiator 1173 that adds Preferably 3%~5%; Stirring is preferably a magnetic stirrer, the stirring speed is 1000r/min, and the stirring time is 12h.

Above-mentioned technical scheme, in step 3, ma-PDMS polymer solution concentration scope 1~5mg/mL, the distance between substrate and UV lamp (365nm) is preferably set to 10~15cli.

Above-mentioned technical scheme, in step 4; Natural lipid is preferably DOPC (1,2-dioleoyl-sn-glycerol-3-phosphocholine), POPC (1-palmitoyl-2-oleoyl -glycero-3-phosphocholine) or DSPC (l,2-l,2-distearoyl-sn-glycero-3-phosphocholine);

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[00681

<img file="CN115382741A_D0005.tif" />

<img file="CN115382741A_D0006.tif" />

DSPC structural formula:

<img file="CN115382741A_D0007.tif" />

Ο The ratio of natural lipid chloroform and glycerol is preferably (40~80) mg: (2~4) mL: (1~3) mL; the rotary evaporation time is preferably 1~2 h, and the hydration time is preferably 40~80 min ; Probe ultrasound is preferably 5 times, the power of the probe is preferably 50W, and the ultrasound response of the probe is preferably 2s each time, and 2s pause 0

Above-mentioned technical scheme, in step 5, preferably the lubricating oil that phase transition can take place is coconut oil (melting point: 23 °C) or palm oil (melting point: 40 °C); The volume ratio of lubricating oil and glycerol-containing lipid vesicle It is preferably 1:9, 2:8 or 3:7; the method used for coating is spin coating, spray coating or dip coating. When dip coating, the dip coating time is preferably 5h. When spray coating is adopted, the spray coating process condition is preferably : adopt compressed air spraying, spraying pressure 1.1~10bar; Spraying liquid flow rate: 150~1000mL/min.

[0070] The terms used in the present invention generally have meanings commonly understood by those of ordinary skill in the art, unless otherwise specified. In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with embodiments.

[0071] In the following examples, various processes and methods not described in detail are conventional methods well known in the art. Down

The materials, reagents, devices, instruments, equipment, etc. used in the above examples can be obtained from commercial sources unless otherwise specified.

Embodiment Below in conjunction with embodiment, further illustrate the present invention.

Embodiment 1

Step 1, polydopamine coating is formed on the surface of metal copper substrate

Configuration concentration is the Tris-HCl dopamine buffer solution of 2mg/mL pH=8.5, and size is that 5*25*75mm metal copper substrate is immersed in above-mentioned solution, dopamine polymerization reaction 24 hours under the condition of 25 °C, takes out metal The copper substrate was rinsed with distilled water for 5 times and dried naturally to obtain the polydopamine substrate.

The polydimethylsiloxane (MA-PDMS) solution preparation of step 2, methacrylate modification:

Get a 100mL dry and clean single-necked flask, PDMS, silane coupling agent, catalyzer DTBL and deionized water are 1:35:1:125 according to molar ratio at room temperature stirring and mixing, then gained solution is placed in In an oven, dehydrate under reduced pressure at 60°C. Then, the photoinitiator 1173 with a mass fraction of 3% was placed in the above mixed solution, and stirred evenly at room temperature to obtain a MA-PDMS solution.

The polydimethylsiloxane (MA-PDMS) film preparation of step 3, methacrylate modification:

Get the MA-PDMS polymer solution (concentration is 2mg/mL, solvent is water) that step 2 prepares, to the MA-PDMS solution of above-mentioned configuration of spraying on the metal copper sheet that has formed polydopamine coating on surface, then in Under UV lamp (365nm), carry out 30s photopolymerization, obtain the polydimethylsiloxane (MA-PDMS) film of methacrylate modification;

Step 4, the preparation of the lipid vesicle of embedding glycerol:

Get 40mg DOPC and dissolve with 2mL chloroform, transfer in the round-bottomed flask, under the condition of 37 DEG C, rotary evaporation under reduced pressure 1h becomes uniform lipid film, then add 1mL glycerol in the round-bottomed flask, hydration under the condition of 60 DEG C for 40min. Then put the flask under an ice bath, and the probe ultrasonically reacted 5 times (power 50W, working for 2s, pausing for 2s), and the glycerol-embedded lipid vesicles were obtained.

Step 5, the construction of self-adaptive super-lubricating gel coat:

Under the condition of higher than coconut oil melting point temperature, coconut oil is mixed with the lipid vesicle of embedding glycerol to obtain coating solution (mixing volume ratio is 1:9), the MA-PDMS membrane that will obtain is immersed in coating Swell in the covering solution for 5 hours, take out the swollen silicone gel and cool it for later use.

Embodiment 2

Step 1, glass substrate surface forms polydopamine coating

Configuration concentration is the sodium hydroxide dopamine buffer solution of 2mg/mL pH=9, and the glass substrate that size is 5*25*75mm is immersed in above-mentioned solution, dopa polymerization reaction 24h at 32 °C, takes out glass substrate Finally, rinse with distilled water for 5 times, and dry naturally to obtain the polydopamine substrate.

The polydimethylsiloxane (MA-PDMS) solution preparation of step 2, methacrylate modification:

Get a 100mL dry and clean single-necked flask, PDMS, silane coupling agent, catalyzer DTBL and deionized water molar ratio are 1:40:2:130 at room temperature stirring and mixing, then gained solution is placed in In an oven, dehydrate under reduced pressure at 60°C. Then, the photoinitiator 1173 (HMPP) with a mass fraction of 5% was placed in the above mixed solution, and stirred evenly at room temperature to obtain a MA-PDMS solution.

The polydimethylsiloxane (MA-PDMS) film preparation of step 3, methacrylate modification:

Get the prepared MA-PDMS polymer solution (concentration is 2mg/mL, solvent is water) of above-mentioned steps 2. Spray the MA-PDMS polymer solution of the above configuration on the glass substrate that has formed a polydopamine coating on the surface, and then carry out 30s photopolymerization under a UV lamp (365nm) to obtain a methacrylate-modified polydimethylsiloxane methane (MA-PDMS) membrane.

Step 4, the preparation of the lipid vesicle of embedding glycerol:

Get 60mg POPC and dissolve with 2mL chloroform, transfer in the round-bottomed flask, under the condition of 37 °C, decompression rotary evaporation 1h becomes uniform lipid film, then add 1mL glycerol in the round-bottomed flask, hydration 60min under the condition of 60 °C. Then put the flask under an ice bath, and the probe ultrasonically reacted 5 times (power 50W, working for 2s, pausing for 2s), and the glycerol-embedded lipid vesicles were obtained.

Step 5, the construction of adaptive super lubricating gel coat:

Under the temperature condition higher than the melting point of palm oil, palm oil is mixed with the lipid vesicle of embedding glycerol to obtain coating solution (mixing volume ratio is 2:8), the MA-PDMS membrane that will obtain is immersed in coating Swell in the covering solution for 5 hours, take out the swollen silicone gel and cool it for later use.

The organosilicon gel prepared by embodiment 2 is detected, and the detection result is as shown in Figure 2 and Figure 3. Among Fig. 2, A, B are the water contact angle figure and the sliding angle figure of the glass that is coated with superlubricating organogel coating in embodiment 2 respectively without sand friction surface; The n-hexane contact angle and sliding angle diagrams of organogel-coated glass after 20 times of sand spin rubbing. Fig. 3 is the physical picture that will be coated with the glass of super-lubricating organogel coating in embodiment 2 and rotate and rub 20 times in sand. It can be seen from the figure that the super-lubricating organic gel coating of the present invention has self-adaptability, greatly enhances the friction resistance of the lubricating material without losing the interface lubricity, and effectively prolongs the service life of the lubricating coating.

[0096] Apparently, the above-mentioned implementation is only an example for clearly illustrating, rather than a limitation to the embodiment. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the embodiments here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.