CN106009943A - Green, size-controlled, substrate-independent underwater super-oleophobic coating and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of oleophobic coatings, and discloses a method for preparing a green size-controllable and substrate-independent underwater super-oleophobic coating, including the steps of soaking or spreading a sodium alginate solution on the surface of the substrate, and _Putting the processed substrate surface into CaCl solution to obtain the step of calcium alginate coating; also discloses the coating prepared by the above method; beneficial effect of the present invention: it can be used for marine antifouling coatings, oil/water separation, Oil pipeline treatment and fluid drag reduction, bioadhesion, microfluidic technology and food containers and other fields; the method is simple, the size of the coating can be controlled, and it is applicable to substrates of any shape, chemical composition and properties; changing the preparation method can also obtain The underwater super oleophobic film that does not depend on the substrate, the raw materials used are ready-made and cheap, no pollution to the environment, safe and non-toxic, and does not require special equipment. It is different from the current fluorine-containing film that is expensive, toxic and harmful, and will lose its super oleophobic properties underwater. Compared with other materials, it has a good application prospect.

Description

Green size-controllable and substrate-independent underwater superoleophobic coating and preparation method

technical field

The invention relates to the technical field of oleophobic coatings, in particular to a green size-controllable and substrate-independent underwater super-oleophobic coating and a preparation method thereof.

Background technique

Oil adhesion is a major limiting factor in many applications, from industrial areas to kitchens. Oleophobic surfaces have high expectations and great promise in marine antifouling coatings, oil/water separation, industrial metal cleaning, oil pipeline treatment, and fluid drag reduction, bioadhesion, microfluidics, and food container applications. Although great progress has been made in the research of oleophobic surfaces, the property of oleophobicity is still lacking. Some recent studies have prepared superoleophobic porous fluorinated membrane surfaces by injecting fluorinated liquid into designated positions. The preparation of such films is cumbersome for most substrates and can only be prepared on a few materials such as textiles, glass, silicon wafers, silica, and meshes. In addition, the excessive use of fluorine-containing chemicals may cause environmental pollution, which limits their applications. An ideal oleophobic coating should be oleophobic to a variety of oils, and the preparation process is simple, independent of the size, shape and composition of the base material, and the materials used in the preparation are environmentally friendly and non-polluting.

Sodium alginate is a natural polyanionic polysaccharide extracted from brown seaweed and is generally recognized as safe (FDA). Its coating can act as a carrier for antimicrobial compounds and antioxidants to maintain high concentrations of preservatives on the surface of foods. It is an inexpensive, biocompatible, and environmentally friendly biopolymer that has wide applications in the biotechnology industry such as non-toxic food additives, thickeners, gelling agents, emulsifiers, and colloidal stabilizers. Sodium alginate can cross-link multivalent metal cations such as Ca2 ⁺ and produce strong gel, which has been widely used in tissue engineering.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of traditional oleophobic coating materials such as cumbersome preparation, substrate dependence, and environmental pollution, and to provide a method for preparing a green underwater super oleophobic coating that is controllable in size and does not depend on the substrate. Using safe and non-toxic sodium alginate as the experimental raw material, an environmentally friendly material with good oleophobic effect was prepared through a simple and substrate-independent preparation method, which can then be widely used in marine antifouling coatings, oil/water separation, Industrial metal cleaning, oil pipeline treatment and fluid drag reduction, bioadhesion, microfluidics and food containers.

The present invention is a method for preparing a green size-controllable and substrate-independent underwater super-oleophobic coating, comprising:

Step 1. Soak or spread sodium alginate solution on the substrate surface;

Step 2, putting the treated substrate surface into a CaCl ₂ solution to obtain a calcium alginate coating.

Further, before step 1, pretreatment of the substrate surface is also included: first use deionized water, acetone, and ethanol to use a KH7200E ultrasonic cleaner to ultrasonicate the glass sheet for 10-15 minutes under the power of 75-100W electrosonic , then rinsed with deionized water for 3-5 times, then heated in a solution with a volume ratio of H ₂ O ₂ : H ₂ SO ₄ of 1:3 for 1-1.5 hours, rinsed with deionized water for 3 times to remove the residual solution, and used Nitrogen blow dry, plasma treatment.

Further, the preparation of sodium alginate solution in step 1: sodium alginate was dissolved in deionized water at a mass concentration of 1.5 g/100 ml; the mass concentration of CaCl ₂ solution in step 2 was 10%.

Further, the material of the substrate is glass, silicon wafer, silica, steel sheet, mica, PET; the size, shape and composition of the substrate are determined according to actual needs.

Further, the base is the inner wall of the food container.

A green size-controllable and substrate-independent underwater superoleophobic coating, the underwater superoleophobic coating material is calcium alginate.

Further, the underwater super-oleophobic coating is made by the above-mentioned preparation method

The beneficial effects of the present invention are:

(1) The substrate of the underwater superoleophobic coating can be of any size, shape and composition, and is universal;

(2) It has stable underwater superoleophobic properties for various oils;

(3) The preparation method is simple, and the raw materials used are environmentally friendly, safe and non-toxic;

(4) The equipment is simple and the materials are cheap;

(5) It can be widely used in the fields of marine antifouling coatings, oil/water separation, industrial metal cleaning, oil pipeline treatment, fluid drag reduction, bioadhesion, microfluidic technology and food containers.

Description of drawings

Fig. 1 is a scanning electron microscope picture and a contact angle picture of a calcium alginate coating according to an embodiment of the present invention.

Among them: a) scanning electron microscope picture; b) water contact angle picture in air; c) 1,2-dichloroethane contact angle picture in air; d) underwater 1,2-dichloroethane contact angle picture Picture; e) The contact angle data map of different oils under water.

A) in Fig. 2 is the underwater 1,2-dichloroethane rolling angle picture of the calcium alginate coating of the embodiment of the present invention; b) in Fig. Stained silicone oil as dirt, self-cleaning picture of calcium alginate coating.

A) in Fig. 3 is the picture before and after coating calcium alginate coating on the planar substrate of different materials; Among b) in Fig. 3 is the picture of underwater contact angle before and after coating calcium alginate coating on different substrates.

Figure 4 is a picture of calcium alginate coated membranes of different shapes without substrate support.

Among them: a) planar; b) tubular.

Figure 5 is a self-cleaning picture before and after coating calcium alginate film in a normal bottle.

detailed description

Specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be regarded as isolated, and they can be combined with each other to achieve better technical effects. In the drawings of the following embodiments, the same reference numerals appearing in each drawing represent the same features or components, which can be applied in different embodiments.

In an embodiment of the present invention, a method for preparing a green size-controllable and substrate-independent underwater super-oleophobic coating includes:

Step 1. Soak or spread sodium alginate solution on the substrate surface;

Step 2, putting the treated substrate surface into a CaCl ₂ solution to obtain a calcium alginate coating.

Preferably, before step 1, the pretreatment of the substrate surface is also included: first use deionized water, acetone, and ethanol to use a KH7200E ultrasonic cleaner to ultrasonicate the glass sheet for 10-15 minutes under the electric ultrasonic power of 75-100W , then rinsed with deionized water for 3-5 times, then heated in a solution with a volume ratio of H ₂ O ₂ : H ₂ SO ₄ of 1:3 for 1-1.5 hours, rinsed with deionized water for 3 times to remove the residual solution, and used Nitrogen blow dry, plasma treatment.

Preferably, the preparation of sodium alginate solution in step 1: Sodium alginate is dissolved in deionized water at a mass concentration of 1.5g/100ml; the mass concentration of CaCl solution in step ₂ is 10%.

Preferably, the material of the substrate is glass, silicon wafer, silica, steel sheet, mica, PET; the size, shape and composition of the substrate are determined according to actual needs.

Preferably, the substrate is an inner wall of a food container.

A green size-controllable and substrate-independent underwater superoleophobic coating, the underwater superoleophobic coating material is calcium alginate.

Preferably, the underwater super-oleophobic coating is made by the preparation method as described in any one of claims 1-3.

The conditions for sodium alginate to form a film on the surface of an object and the requirements for external conditions are very simple. If it is used as a surface coating, it can be directly painted on the surface of the carrier, but in the embodiment of the present invention, it is necessary to collect relevant data. Data collection Conditions require that the film has a uniform thickness, a smooth surface, and is easy to separate from the carrier. Therefore, the film carrier needs to be very clean. In actual use, the substrate surface does not need to be very smooth. In the following examples, without loss of generality, the substrate is made of glass. .

Example 1

Use deionized water to use KH7200E ultrasonic cleaner to ultrasonicate the glass sheet at the power of 75-100W for 10-15min, then use acetone to ultrasonicate the glass sheet at the same power for 10-15min, and finally in ethanol Sonicate the glass piece at the same power for 10-15min, then rinse the glass piece 3 times with deionized water and heat it for 1-1.5h in a solution with a volume ratio of H ₂ O ₂ : H ₂ SO ₄ of 1:3, using deionized water Rinse 3-5 times to remove residual solution to obtain a clean glass sheet.

Add a certain volume of sodium alginate solution with a mass concentration of 1.5g/100ml dropwise on the plasma-treated glass sheet, spread the liquid with the help of a bacteria-coating rod and let it stand for a while, then put the glass covered with sodium alginate The tablets were placed in a ₁₀ % CaCl solution to obtain a calcium alginate oleophobic coating.

Measurement of contact angles of water, 1,2-dichloroethane in air, and underwater of 1,2-dichloroethane, silicone oil, chloroform, edible oil, and n-decane using the resulting calcium alginate coating The contact angle and the rolling angle of 1,2-dichloroethane under water were taken and plotted, as shown in Figure 1, from which it can be seen that the inclination angle is less than 2°, that is to say, when the inclination angle is 2° , the oil droplets began to roll, proving that the calcium alginate coating had little adhesion to the oil.

Example 2

Use deionized water to use KH7200E ultrasonic cleaner to ultrasonicate the glass sheet at the power of 75-100W for 10-15min, then use acetone to ultrasonicate the glass sheet at the same power for 10-15min, and finally in ethanol Sonicate the glass piece at the same power for 10-15min, then rinse the glass piece 3 times with deionized water and heat it for 1-1.5h in a solution with a volume ratio of H ₂ O ₂ : H ₂ SO ₄ of 1:3, using deionized water Rinse 3-5 times to remove residual solution to obtain a clean glass sheet.

As shown in Figure 2, draw a mark in the middle of the glass sheet with a water pen, divide it into two parts, wrap half of it with plastic wrap (blank comparison), after plasma treatment, add a certain volume of alginic acid with a mass concentration of 1.5g/100ml The sodium solution was added dropwise on the plasma-treated glass plate, and the liquid was flattened with the help of a bacteria-coating stick and then allowed to stand for a period of time, and then the glass plate covered with sodium alginate was placed in a 10% CaCl ₂ solution to obtain Calcium alginate oleophobic coating, while the other half wrapped in plastic wrap was not prepared with calcium alginate coating.

Soak the glass piece in deionized water for 10min, apply oil red stained silicone oil (as dirt) on half of the glass piece with calcium alginate coating and half without oleophobic coating, rinse the silicone oil on the glass piece with deionized water, Taking a self-cleaning video of the calcium alginate coating during the washing process, it can be found that half of the silicone oil coated with calcium alginate is washed off quickly, while the silicone oil on a normal glass sheet without an oleophobic coating is difficult to wash off, resulting in calcium alginate The coating has the property of underwater superoleophobicity, which can be used for self-cleaning of the carrier.

Example 3

As shown in Figure 3, using substrates of different materials, two substrates each of steel sheet, silicon sheet, polyethylene terephthalic acid (PET) and mica sheet, and measuring the underwater 1,2-dichloro Ethane contact angle, another plasma treatment.

Add a certain volume of sodium alginate solution with a mass concentration of 1.5g/100ml dropwise on the substrate that has been treated with plasma, spread the liquid with the help of a smear stick and let it stand for a while, and then put the substrate covered with sodium alginate Put it into 10% CaCl2 solution to obtain calcium alginate oleophobic coating, and measure the contact angle of 1,2-dichloroethane underwater, and plot the contact angle data of the two substrates to obtain the coating on the coating. After the calcium alginate coating, the contact angles of these substrates under water are all greater than 150°, becoming a super oleophobic surface.

Example 4

Take a 10 x 10cm glass plate and an ordinary glass bottle with deionized water and use a KH7200E ultrasonic cleaner to ultrasonicate for 10-15min at a power of 75-100W, and then use acetone to sonicate for 10-15min at the same power , and finally ultrasonicated in ethanol at the same power for 10-15min, then rinsed with deionized water for 3-5 times and heated in a solution with a volume ratio of H ₂ O ₂ : H ₂ SO ₄ of 1:3 for 1-1.5h , use deionized water to rinse 3-5 times to remove residual solution to obtain clean glass plates and glass bottles.

Add a certain volume of sodium alginate solution with a mass concentration of 1.5g/100ml dropwise on the plasma-treated glass sheet, spread the liquid with the help of a bacteria-coating rod and let it stand for a while, then put the glass covered with sodium alginate Put the film into 10% CaCl ₂ solution to get calcium alginate oleophobic coating, which can be carefully peeled off and photographed. Pour the sodium alginate solution with a mass concentration of 1.5g/100ml into the plasma-treated glass bottle, then pour out the sodium alginate solution, and quickly pour 10% CaCl2 solution to obtain the inner layer coated seaweed Calcium alginate coated glass bottle, peel off the coating and pour oil red dyed edible oil, take a picture, as shown in Figure 4, you can see that the calcium alginate coating can exist independently without the support of the substrate, and is a flat film Or by a tubular membrane of a certain liquid.

Example 5

Go to two ordinary glass bottles and use deionized water to use the KH7200E ultrasonic cleaner. Ultrasonic at a power of 75-100W for 10-15 minutes, then use acetone for 10-15 minutes at the same power, and finally Sonicate in ethanol at the same power for 10-15min, then rinse with deionized water for 3-5 times, heat in a solution with a volume ratio of H2O2 _{: H2SO4} of ₁ : ₃ for 1-1.5h, use deionized Rinse with water three times to remove the residual solution to obtain clean glass bottles, one of which was treated with plasma, and the other was not treated.

Pour 1.5g/100ml sodium alginate solution into the plasma-treated glass bottle, then pour out the sodium alginate solution, and quickly pour 10% _CaCl2 solution to get the inner layer coated with calcium alginate Layer glass bottles, soak in deionized water for 10min, pour oil red dyed edible oil into two glass bottles, tilt and rotate the two glass bottles, take a self-cleaning video, you can see that the calcium alginate coating is coated The high-quality bottle will not stick to the cooking oil, and the inner wall of the bottle is still very clean, while the inner wall of an ordinary glass bottle will be covered with a layer of cooking oil. As shown in Figure 5.

The beneficial effects of the present invention are:

(1) The substrate of the underwater superoleophobic coating can be of any size, shape and composition, and is universal;

(2) It has stable underwater superoleophobic properties for various oils;

(3) The preparation method is simple, and the raw materials used are environmentally friendly, safe and non-toxic;

(4) The equipment is simple and the materials are cheap;

(5) It can be widely used in the fields of marine antifouling coatings, oil/water separation, industrial metal cleaning, oil pipeline treatment, fluid drag reduction, bioadhesion, microfluidic technology and food containers.

Although several embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments herein can be changed without departing from the spirit of the present invention. The above-mentioned embodiments are only exemplary, and the embodiments herein should not be used as limitations on the scope of rights of the present invention.

Claims (7)

1. A method for preparing a green size-controllable and substrate-independent underwater super-oleophobic coating, characterized in that it comprises: Step 1. Soak or spread sodium alginate solution on the substrate surface; Step 2, putting the treated substrate surface into a CaCl ₂ solution to obtain a calcium alginate coating. 2. the size of green as claimed in claim 1 is controllable and does not depend on the preparation method of the underwater super-oleophobic coating of substrate, it is characterized in that, before step 1, also comprise the pretreatment of substrate surface: first use respectively Ionized water, acetone, and ethanol use a KH7200E ultrasonic cleaner to sonicate the glass sheet for 10-15 minutes at a power of 75-100W, then rinse it with deionized water for 3-5 times and place it in a volume ratio of H ₂ O ₂ : H ₂ SO ₄ is 1:3 solution heating 1-1.5h, rinse with deionized water 3 times to remove residual solution, dry with nitrogen, plasma treatment. 3. the size of green as claimed in claim 1 is controllable and does not depend on the preparation method of the underwater super-oleophobic coating of substrate, it is characterized in that, the preparation of sodium alginate solution in step 1: sodium alginate is with mass concentration 1.5g/100ml is dissolved in deionized water; the mass concentration of CaCl ₂ solution in step 2 is 10%. 4. as claimed in any one of claim 1-3, the size of the green is controllable and does not depend on the preparation method of the underwater super-oleophobic coating of the substrate, it is characterized in that, the material of the substrate is glass, silicon wafer, Silica, steel sheet, mica, PET; the size, shape and composition of the substrate are determined according to actual needs. 5. the size controllable as described in any one of claim 1-3 and the preparation method of the underwater superoleophobic coating that does not rely on substrate, it is characterized in that, described substrate is food container inner wall. 6. A green size-controllable and substrate-independent underwater super-oleophobic coating, characterized in that the underwater super-oleophobic coating material is calcium alginate. 7. A kind of green size controllable as claimed in claim 6 and not relying on the underwater super oleophobic coating of substrate, it is characterized in that, the underwater super oleophobic coating is made of as any one of claims 1-3 Prepared by the described preparation method.