阅读说明：本技术 一种提高材料表面防垢性能的方法 (Method for improving anti-scaling performance of material surface ) 是由 田雪林 陈雨欣 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种提高材料表面防垢性能的方法。方法包括如下步骤：S1.基底表面预处理：将平坦基底表面清洗去除表面污渍,保持表面洁净；S2.等离子体处理：将洁净基底两面分别进行等离子处理,使其表面充分羟基化,等离子处理强度为30～50w,处理时间5～10min；S3.表面修饰：将羟基化基底浸入PDMS液体中,在80～150℃下反应12～48h,反应后除去多余的PDMS,清洗吹干即可。本发明通过在光滑平坦基底表面接枝PDMS,与普通烷基分子刷和含氟低表面能分子修饰的同种材料相比,表面结垢量减少了50％以上,修饰表面疏水,粗糙度与原基底相近,不影响基底形貌,且适用基底范围广,成本低,无毒无污染,制备工艺简单,可适用于规模化生产。(The invention discloses a method for improving the anti-scaling performance of the surface of a material. The method comprises the following steps: s1, pretreatment of the surface of a substrate: cleaning the surface of the flat substrate to remove surface stains and keeping the surface clean; s2, plasma treatment: respectively carrying out plasma treatment on two surfaces of the clean substrate to ensure that the surfaces of the clean substrate are fully hydroxylated, wherein the plasma treatment strength is 30-50 w, and the treatment time is 5-10 min; s3, surface modification: and (3) immersing the hydroxylated substrate into PDMS liquid, reacting for 12-48 h at 80-150 ℃, removing the redundant PDMS after reaction, and cleaning and blow-drying. According to the invention, PDMS is grafted on the surface of the smooth and flat substrate, compared with common alkyl molecular brushes and the same material modified by fluorine-containing low surface energy molecules, the surface scaling amount is reduced by more than 50%, the modified surface is hydrophobic, the roughness is similar to that of the original substrate, the substrate appearance is not influenced, the substrate application range is wide, the cost is low, no toxicity or pollution is caused, the preparation process is simple, and the method is suitable for large-scale production.)

1. A method for improving the anti-scaling performance of the surface of a material is characterized by comprising the following steps:

s1, pretreatment of the surface of a substrate: cleaning the surface of the flat substrate to remove surface stains and keeping the surface clean;

s2, plasma treatment: respectively carrying out plasma treatment on two sides of a clean substrate to ensure that the surface of the clean substrate is fully hydroxylated, wherein the plasma treatment strength is 30-50 w, and the front side and the back side are respectively treated for 5-10 min;

s3, surface modification: and (3) immersing the hydroxylated substrate into PDMS liquid, reacting at the temperature of 80-150 ℃ for 12-48 h, removing the redundant PDMS after reaction, cleaning and drying.

2. The method for improving the antifouling property of the surface of material according to claim 1, wherein said cleaning means in S1 is operated as: and sequentially putting the substrate into acetone, isopropanol and deionized water solvents for ultrasonic cleaning.

3. The method for improving the scale prevention performance of the surface of the material according to claim 1, wherein the intensity of the plasma treatment in S2 is 30-50 w, and the front and back sides are treated for 5-10 min respectively.

4. The method for improving the scale prevention performance of the surface of the material according to claim 1, wherein the reaction temperature of the surface modification in S3 is 80-150 ℃, and the reaction time is 12-48 h.

5. The method for improving the scale prevention performance of the surface of a material according to claim 4, wherein the molecular weight of the PDMS in S3 is 2000-9000.

6. The method for improving the scale prevention performance of the surface of a material according to claim 5, wherein the molecular weight of the PDMS in S3 is 5000-7000.

7. The method for improving the scale prevention performance of the surface of a material according to claim 4, wherein the PDMS in S3 comprises a methyl, amino, hydroxyl, vinyl or epoxy terminated PDMS.

8. The method for improving the antifouling property of the surface of material according to claim 1, wherein the specific operation of removing the excess PDMS in S3 is as follows: and sequentially putting the reacted substrate into toluene, isopropanol and deionized water for cleaning.

9. The method for improving the scale prevention performance of the surface of a material according to any one of claims 1 to 8, wherein the flat substrate comprises glass, silicon wafer, metal sheet or plastic.

Technical Field

The invention relates to the technical field of anti-scaling treatment, in particular to a method for improving the anti-scaling performance of a material surface.

Background

The water used for daily life and industrial water are generally rich in inorganic salt ions such as calcium ions, potassium ions and the like, when the ion concentration is increased and is deposited on the surface of a pipeline or a device, the machine is generally damaged, the energy consumption of production is increased, the later clearing work can prolong the working hours, increase the production cost and reduce the service life of equipment. The currently used descaling methods include three methods, namely physical methods, chemical methods and novel materials. Physical methods such as electric field scale prevention and variable frequency scale prevention have very limited scale inhibition effect; chemical methods including various antiscalants suffer from poor versatility and the need for post-treatment. Although novel materials such as polytetrafluoroethylene or low surface energy substances with fluorine modified on the surface show relatively excellent anti-fouling performance, researches prove that the fluorine-containing substances are not environment-friendly and can cause certain harm to the environment and human bodies. Therefore, the conventional descaling method has certain application limitation.

With the discovery and research of the hydrophobic phenomenon, the water repellency of the material surface achieves to a certain extent the limitation of inorganic salt scaling on the surface. Hydrophobic surfaces are achieved primarily by surface structure and low surface energy modification, and surface antiscaling can only be achieved by low surface energy modification, since the coarse structure favors heterogeneous nucleation crystallization. However, most of the currently used low surface energy modifiers are fluorine-containing substances, and the pollution cannot be ignored. CN105199497A discloses a preparation and coating method of an anticorrosion and antiscale coating material, the coating material is obtained by mixing polytetrafluoroethylene emulsion with graphene and titanium dioxide, the surface energy of polytetrafluoroethylene is reduced by the graphene and the titanium dioxide, and the anticorrosion and antiscale properties of the surface of a base material are comprehensively improved, but fluorine-containing substances such as polytetrafluoroethylene can generate certain harm to the environment and human body, and are not suitable for practical production and application, and no evidence is provided for the reduction effect of the surface scaling amount in the publication, and whether certain antiscale properties can be obtained cannot be explained.

Therefore, it would be desirable in the art to provide a method for significantly reducing the amount of fouling on the surface of a material and improving the anti-fouling performance of the surface of the material, so as to reduce the damage to machinery caused by fouling during use.

Disclosure of Invention

The invention aims to solve the technical problems that the existing surface anti-scaling method cannot well reduce the surface scaling amount and the used material has certain harm to the environment and human body, and provides a method for improving the surface anti-scaling performance of the material.

The above purpose of the invention is realized by the following technical scheme:

a method for improving the anti-scaling performance of the surface of a material comprises the following steps:

s1, pretreatment of the surface of a substrate: cleaning the surface of the flat substrate to remove surface stains and keeping the surface clean;

s2, plasma treatment: respectively carrying out plasma treatment on two sides of a clean substrate to ensure that the surface of the clean substrate is fully hydroxylated, wherein the plasma treatment strength is 30-50 w, and the front side and the back side are respectively treated for 5-10 min;

s3, surface modification: and (3) immersing the hydroxylated substrate into PDMS liquid, reacting at the temperature of 80-150 ℃ for 12-48 h, removing the redundant PDMS after reaction, cleaning and drying.

The blow-drying in S3 is preferably performed by inert gas blow-drying, such as nitrogen blow-drying.

According to the method for improving the surface antiscaling performance, the flexible molecular brush PDMS is grafted on the flat surface to form a liquid-like surface, so that on one hand, the free rotation of a flexible dynamic molecular chain on the surface can inhibit the formation of a crystal ordered structure, and thus the antiscaling is realized; on the other hand, the modification of the surface monomolecular layer does not influence the surface appearance, and the raw materials are cheap and easy to obtain, nontoxic and environment-friendly, the preparation method is simple, and the applicable substrate is wide.

The linear polydimethylsiloxane molecular brush (PDMS) adopted by the invention has low raw material cost, no toxicity and no pollution, the roughness of the surface of the linear PDMS is approximately the same as that of the original substrate after the linear PDMS is modified, the original appearance is not changed, and the linear PDMS molecular brush can be applied to various surfaces, so that the application range is wide.

The surface pretreatment is carried out before the substrate treatment, impurities such as surface stains and the like are removed, and crystal nucleation sites are provided if the impurities such as the stains and the like exist on the surface of the substrate, so that the heterogeneous nucleation possibility is greatly improved, and the surface scaling amount is increased.

The plasma treatment of the substrate mainly has the function of grafting the linear polydimethylsiloxane to provide chemically bonded active sites on the surface of the substrate.

The method of the invention can realize the main action mechanism of improving the surface antiscaling performance of the material, and comprises the following steps:

(1) the formation of a crystal ordered structure is inhibited through the free rotation and movement of the surface flexible molecular chain PDMS, so that the scale inhibition is realized.

(2) The low surface energy surface inhibits scaling, and the linear PDMS modified surface has hydrophobicity and lower surface energy and can inhibit scaling to a certain degree.

The specific cleaning operation in S1 is preferably: and sequentially putting the substrate into acetone, isopropanol and deionized water solvents for ultrasonic cleaning. The ultrasonic treatment is carried out for about 15min, the substrate is sequentially cleaned by acetone, isopropanol and deionized water, and the substrate is cleaned by solvents with different polarities according to a certain sequence, so that impurities with different polarities on the surface can be cleaned to the greatest extent.

Preferably, the intensity of the plasma treatment in S2 is 30-50 w, and the front and back sides are treated for 5-10 min respectively.

The whole treatment effect of the plasma is influenced by the treatment time and the strength of the plasma, and the low strength causes the low grafting density and the poor hydrophobicity; if the strength is high, the grafting density is too high, and the flexibility is not provided. During actual treatment, the strength of the relevant plasmas is matched with the treatment time, the time can be shorter when the strength is high, the time can be longer when the strength is low, and the grafting density is easy to be too low and the hydrophobicity is poor when the time is short; if the strength is high, the grafting density is easy to be too high, and the flexibility is not provided.

The grafting reaction temperature is limited for the following reasons: if the reaction temperature is too low, polydimethylsiloxane cannot be grafted on the surface, and if the reaction temperature is too high, polydimethylsiloxane is easily decomposed, so that the proper reaction temperature range is limited to 80-150 ℃.

The grafting reaction time is limited for the following reasons: if the reaction time is too short, the polydimethylsiloxane cannot be completely grafted on the surface, and if the reaction time is too long, the polydimethylsiloxane is easy to crosslink, so that the liquid level performance is influenced, so that the proper reaction time is limited to 12-48 h.

Preferably, the reaction temperature of the surface modification in S3 is 100 ℃ and the reaction time is 24 h.

Preferably, the PDMS in S3 has a molecular weight of 2000-9000. Effect of polydimethylsiloxane molecular weight on surface properties: the liquid-like character of the surface decreases with increasing molecular weight, and either too high or too low molecular weight can affect the anti-fouling properties of the linear polydimethylsiloxane-modified surface. The linear polydimethylsiloxane with the molecular weight of 2000-9000 has good modification effect and liquid-like property.

Further preferably, the molecular weight of the PDMS in S3 is 5000-7000.

The PDMS in S3 of the invention comprises methyl, amino, hydroxyl, vinyl or epoxy terminated PDMS, and the molecular chain skeleton of the PDMS is a siloxane chain, so that the PDMS has flexibility and can make the modified surface show liquid-like characteristics. Other surface modification means may be, for example, graft-crosslinked pdms (cpdms), Perfluorooctyltrichlorosilane (PFOS) or Octadecyltrichlorosilane (OTS), the resulting surface not exhibiting liquid-like properties.

Preferably, the specific operation of removing the excess PDMS in S3 is: and sequentially putting the reacted substrate into toluene, isopropanol and deionized water for cleaning. If the surface is not cleaned, PDMS adheres to the surface, which causes non-uniformity of the surface and affects the flatness of the surface, thereby being beneficial to heterogeneous nucleation and affecting the anti-scaling performance. And (3) cleaning the modified surface by adopting a specific solvent in sequence, dissolving redundant PDMS by using toluene, rinsing by using isopropanol, and cleaning by using deionized water to take away surface liquid stains.

The method for improving the anti-scaling performance of the material surface has wide application range, and can better improve the anti-scaling performance of the surfaces of various base materials, wherein the preferred base materials comprise glass, silicon wafers, metal sheets or plastics.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a method for improving the surface anti-scaling performance of a material, which obviously improves the surface anti-scaling performance of the material by grafting a linear Polydimethylsiloxane (PDMS) molecular brush on the surface of a smooth and flat substrate, reduces the surface scaling amount by more than 50 percent compared with the common alkyl molecular brush and the same material modified by fluorine-containing low surface energy molecules, and has excellent anti-scaling performance.

(2) The invention adopts the flexible monomolecular brush PDMS for modification, the flat surface is hydrophobic after the modification, the surface roughness is similar to the original substrate, the substrate appearance is not influenced, the substrate application range is wide, and the invention is suitable for the treatment of various substrates such as glass, silicon wafers, metal sheets or plastics.

(3) The method of the invention adopts PDMS as the raw material, which has low cost, no toxicity and no pollution, and simple preparation process, and is suitable for large-scale production.

Drawings

FIG. 1 is a simulation of the molecular structure of the methyl terminated linear PDMS surface used in example 1.

FIG. 2 is an atomic force microscope image of the surface of the normal glass plate and the PDMS-modified glass plate obtained in example 1.

Fig. 3 is a photograph of the contact angle of the surface of a normal glass sheet, the resulting PDMS-modified glass sheet, and the surface of a perfluorooctyltrichlorosilane-modified glass sheet to water.

FIG. 4 is a comparison of the fouling behavior of PDMS-modified glass sheets after fouling experiments with Crosslinked PDMS (CPDMS), Perfluorooctyltrichlorosilane (PFOS), Octadecyltrichlorosilane (OTS) -modified glass sheets and common glass sheets.

FIG. 5 is a diagram of a simple apparatus for scale control experiment, which simulates natural evaporation of the environment and observes the scaling phenomenon of the substrate on the three-phase contact line.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.