阅读说明：本技术 高黏附准超疏水材料及其制备方法 (High-adhesion quasi-super-hydrophobic material and preparation method thereof ) 是由 王萍 叶旭 张岩 李媛媛 徐岚 刘福娟 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种高黏附准超疏水材料及其制备方法,包括以下步骤：将聚氨酯溶解于N,N-二甲基甲酰胺中,得到粘度范围值在15mPas-25mPas之间,电导率范围值在6.40s/cm-10.71s/cm之间的电喷溶液。采用静电喷雾法,将所述电喷溶液喷射至基材的表面,使得所述基材的表面附着有聚氨酯微球,从而得到高黏附准超疏水材料。本发明高黏附准超疏水材料及其制备方法,其制备方法简单,制备过程不需要复杂的设备,制备得到的高黏附准超疏水材料达到超疏水或准超疏水的性能,同时由于聚氨酯特殊的化学组成使高黏附准超疏水材料具有高粘附性。(The invention discloses a high-adhesion quasi-super-hydrophobic material and a preparation method thereof, and the preparation method comprises the following steps: the polyurethane is dissolved in N, N-dimethylformamide to obtain an electrospray solution with the viscosity ranging from 15mPas to 25mPas and the conductivity ranging from 6.40s/cm to 10.71 s/cm. And spraying the electric spraying solution to the surface of the base material by adopting an electrostatic spraying method, so that polyurethane microspheres are attached to the surface of the base material, and thus the high-adhesion quasi-superhydrophobic material is obtained. The high-adhesion quasi-superhydrophobic material and the preparation method thereof have the advantages that the preparation method is simple, no complex equipment is needed in the preparation process, the prepared high-adhesion quasi-superhydrophobic material achieves the performance of superhydrophobicity or quasi-superhydrophobicity, and meanwhile, the high-adhesion quasi-superhydrophobic material has high adhesion due to the special chemical composition of polyurethane.)

1. A preparation method of a high-adhesion quasi-superhydrophobic material is characterized by comprising the following steps:

dissolving polyurethane in N, N-dimethylformamide to obtain an electrospray solution with a viscosity ranging from 15mPas to 25mPas and a conductivity ranging from 6.40s/cm to 10.71 s/cm;

and spraying the electric spraying solution to the surface of the base material by adopting an electrostatic spraying method, so that polyurethane microspheres are attached to the surface of the base material, and thus the high-adhesion quasi-superhydrophobic material is obtained.

2. The method for preparing the high-adhesion quasi-superhydrophobic material according to claim 1, wherein the mass ratio of the polyurethane to the N, N-dimethylformamide in the electrospray solution is (0.4-0.9): 20.

3. The method for preparing a highly adhesive quasi-superhydrophobic material according to claim 1, wherein the polyurethane is a thermoplastic polyester polyurethane having a hardness of 85A.

4. The method for preparing a high-adhesion quasi-superhydrophobic material according to claim 1, wherein the parameters of the electrostatic spraying method comprise: the temperature is 25 ℃, the humidity is 60-65%, the propelling speed is 0.4-1.2 mL/h, the propelling quantity is 1-1.2mL, the voltage is 12-20kV, the diameter of a spraying needle is 0.34mm, and the distance from the spraying needle to a receiving plate is 15 cm.

5. The method for preparing the high-adhesion quasi-superhydrophobic material according to claim 1, wherein the electrostatic spraying method employs a flat receiving device on which a substrate for receiving the polyurethane microspheres is laid.

6. The method of claim 5, wherein the substrate comprises silicone oil paper.

7. The method for preparing the high-adhesion quasi-superhydrophobic material according to claim 6, wherein the contact angle of the silicone oil paper is greater than 100 °.

8. The high-adhesion quasi-superhydrophobic material is characterized by comprising a substrate and polyurethane microspheres attached to the surface of the substrate, wherein the polyurethane microspheres contain carbamate groups and benzene ring groups.

9. The high adhesion quasi-superhydrophobic material of claim 8, wherein the contact angle of the high adhesion quasi-superhydrophobic material ranges from 135-145 °.

10. The high-adhesion quasi-superhydrophobic material of claim 8, wherein the polyurethane microspheres have a particle size ranging from 1.3 m to 1.6m and an aspect ratio ranging from 1.0 m to 1.8 m.

Technical Field

The invention relates to the technical field of hydrophobic materials, in particular to a high-adhesion quasi-super-hydrophobic material and a preparation method thereof.

Background

Over the last two decades, superhydrophobic materials have found sufficient utility in many areas, such as: self-cleaning, oil-water separation, filtration, bioengineering, transportation of tiny water drops, and the like. In nature, the phenomenon of super-hydrophobicity is seen everywhere, such as lotus leaf, rose petal, peach peel and the like. The principle of many super-hydrophobic materials uses the hydrophobic property of lotus leaves as reference: the lotus leaf surface has many micron-sized mastoids, and the surface of the mastoids is covered with wax with low surface energy, so that the lotus leaf surface has excellent hydrophobicity and self-cleaning property by the combined action. Based on this, the processing of micro-nano structures is often used to prepare super-hydrophobic materials.

The polyurethane is a polymer with a linear chain segment structure and more carbamate groups in a molecular chain, and has certain high elasticity, tensile strength, tearing strength and air permeability. The method is widely applied to the fields of high-speed rail construction, automobile manufacturing, sensors and the like. In particular, various hydrophobic studies have been conducted on polyurethanes in order to be used in some severe environments (e.g., humid environments). For the hydrophobic treatment of polyurethane, it is common to introduce low surface energy groups (fluorine or silicon) or to prepare a series of micro-nano structures by a template method, a hydrothermal method and the like. However, these methods are not only harmful to the environment, but also complicated in process.

The above problems are urgently needed to be improved.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a high-adhesion quasi-superhydrophobic material and a preparation method thereof, the preparation method is simple, no complex equipment is needed in the preparation process, the prepared high-adhesion quasi-superhydrophobic material achieves the performance of super-hydrophobicity or quasi-superhydrophobic, and meanwhile, the high-adhesion quasi-superhydrophobic material has high adhesion due to the special chemical composition of polyurethane.

The invention discloses a preparation method of a high-adhesion quasi-superhydrophobic material, which comprises the following steps:

dissolving polyurethane in N, N-dimethylformamide to obtain an electrospray solution with a viscosity ranging from 15mPas to 25mPas and a conductivity ranging from 6.40s/cm to 10.71 s/cm;

and spraying the electric spraying solution to the surface of the base material by adopting an electrostatic spraying method, so that polyurethane microspheres are attached to the surface of the base material, and thus the high-adhesion quasi-superhydrophobic material is obtained.

Preferably, in the electrospray solution, the mass ratio of the polyurethane to the N, N-dimethylformamide is (0.4-0.9): 20.

Preferably, the polyurethane is a thermoplastic polyester polyurethane having a hardness of 85A.

Preferably, the parameters of the electrostatic spraying method include: the temperature is 25 ℃, the humidity is 60-65%, the propelling speed is 0.4-1.2 mL/h, the propelling quantity is 1-1.2mL, the voltage is 12-20kV, the diameter of a spraying needle is 0.34mm, and the distance from the spraying needle to a receiving plate is 15 cm.

Preferably, the electrostatic spraying method adopts a flat plate receiving device, and a base material for receiving the polyurethane microspheres is laid on the flat plate receiving device.

Further preferably, the substrate comprises silicone oil paper.

Even more preferably, the silicone oil paper has a contact angle > 100 °.

The invention also provides a high-adhesion quasi-super-hydrophobic material which comprises a substrate and polyurethane microspheres attached to the surface of the substrate, wherein the polyurethane microspheres contain carbamate groups and benzene ring groups.

Preferably, the contact angle of the high-adhesion quasi-super-hydrophobic material ranges from 135 DEG to 145 deg.

Preferably, the polyurethane microspheres have a particle size ranging from 1.3 to 1.6m and an aspect ratio ranging from 1.0 to 1.8.

The invention has the following beneficial effects:

according to the preparation method of the high-adhesion quasi-superhydrophobic material, polyurethane is sprayed to the surface of the base material by electrostatic spraying, polyurethane microspheres are formed on the surface of the base material, the roughness of the surface of the base material is increased, so that the contact angle is increased, and the prepared high-adhesion quasi-superhydrophobic material achieves the performance of superhydrophobicity or quasi-superhydrophobicity. Meanwhile, the high-adhesion quasi-super-hydrophobic material has high adhesion due to the special chemical composition of polyurethane.

The preparation method of the high-adhesion quasi-superhydrophobic material is simple, does not need complex equipment in the preparation process, and has application value in the fields of micro-droplet transportation and sensors.

In order to make the aforementioned and other objects, features and advantages of the invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is an SEM image of a highly adherent quasi-superhydrophobic material in example 1 of the present invention;

FIG. 2 is a particle size distribution diagram of polyurethane microspheres in the high-adhesion quasi-superhydrophobic material in example 1 of the invention;

FIG. 3 is a water droplet pattern on the surface of a high-adhesion quasi-superhydrophobic material in example 1 of the present invention;

FIG. 4 is an SEM image of a high-adhesion quasi-superhydrophobic material in example 2 of the invention;

FIG. 5 is a distribution diagram of the particle size of the polyurethane microspheres in the high-adhesion quasi-superhydrophobic material in example 2 of the invention;

FIG. 6 is a water droplet pattern on the surface of a high-adhesion quasi-superhydrophobic material in example 2 of the present invention;

FIG. 7 is an infrared spectrum of a highly adherent quasi-superhydrophobic material in example 1 of the invention;

FIG. 8 is a shape diagram of water drops adhered to the surface of a quasi-superhydrophobic material in example 1 of the invention at different angles;

FIG. 9 is a shape chart of water drops on the surface of a high-adhesion quasi-superhydrophobic material in example 1 of the invention, which changes with time when the water drops are inverted for 180 degrees;

FIG. 10 is a shape chart of water drops adhered to the surface of the quasi-superhydrophobic material in example 2 of the invention, which changes with time when the water drops are inverted by 180 degrees;

FIG. 11 is a graph showing the change of contact angle with time of a water droplet on the surface of a highly adhesive quasi-superhydrophobic material according to example 1 of the present invention.

Reference numerals of the above figures: 1-high adhesion quasi-super-hydrophobic material; 2-water drop.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The silicone oil paper described in examples 1-2 was purchased on the market as a common wrapping paper having a three-layer structure, a first base paper, a second film and a third silicone oil.

The polyurethanes described in examples 1-2 were all thermoplastic polyester polyurethanes with a hardness of 85A. The N, N-dimethylformamide solvent was 100% N, N-dimethylformamide.

In example 1-2, the viscosity of the electrospraying solution can be adjusted to between 15mPas and 25mPas by changing the mass of the polyurethane under the condition of the same mass of the solvent, and the conductivity can be adjusted to between 6.40s/cm and 10.71s/cm by changing the mass of the solvent under the condition of the same mass of the polyurethane. The mass ratio of the polyurethane and the N, N-dimethylformamide solvent disclosed in the examples 1-2 can make the electrojet solution viscosity reach between 15mPas and 25mPas and the electric conductivity reach between 6.40s/cm and 10.71 s/cm.

When the viscosity of the electrospraying solution is too low, electrostatic spraying cannot be carried out, and when the viscosity of the electrospraying solution is too high, electrostatic spinning is carried out, and the sprayed solution is not microspheres but fibers. The appearance of the microspheres is affected by too high conductivity of the electrospraying solution, so that a small amount of fibers are formed, and electrostatic spraying cannot be formed if the conductivity of the electrospraying solution is too low. Therefore, the invention limits the viscosity of the electrospray solution to be between 15mPas and 25mPas and the conductivity to be between 6.40s/cm and 10.71 s/cm.

The contact angle of the silicone oil paper in the embodiment 1-2 of the invention is more than 100 degrees.

When the performance test of the high-adhesion quasi-superhydrophobic material prepared in example 1-2 was performed, the high-adhesion quasi-superhydrophobic material was placed on a receiving device, and then water droplets were dropped onto the surface of the receiving device on which the high-adhesion quasi-superhydrophobic material had polyurethane microspheres.

If the contact angle of the silicone oil paper is less than 100 degrees. When water drops fall on the high-adhesion quasi-superhydrophobic material on the receiving device, due to the hydrophilicity of the receiving device, the water drops are induced to penetrate through gaps among polyurethane microspheres on the high-adhesion quasi-superhydrophobic material to be contacted with the receiving device, so that the hydrophilic false image is caused, and the accuracy of a test result is influenced.

Example 1

0.68g of polyurethane is weighed and dissolved in 20g N N-dimethylformamide solvent at the temperature of 20-25 ℃, and a magnetic stirrer is adopted to stir for 12 hours, so that uniform and transparent electrospray solution is obtained.

And (3) performing electrostatic spraying on the electrically sprayed solution by adopting an electrostatic spraying device, and spraying the electrostatically sprayed solution onto the surface of the silicone oil paper on the flat plate receiving device, so that polyurethane microspheres are attached to the surface of the silicone oil paper substrate, and thus the high-adhesion quasi-superhydrophobic material is obtained. Wherein the parameters of electrostatic spraying are set as follows: the inner diameter of the needle is 0.34mm, the voltage is 20kV, the propelling speed is 0.8mL/h, the propelling quantity is 1.2mL, the temperature is 25 ℃, the relative humidity is 65%, the distance between the flat plate receiving device and the needle (receiving distance) is 15cm, and the receiving surface of the flat plate receiving device is covered with silicone oil paper.

Example 2

This example differs from example 1 in the amount of polyurethane used and in the voltage and the rate of advancement of the electrostatic spray. Specifically, the method comprises the following steps:

0.48g of polyurethane is weighed and dissolved in 20g N N-dimethylformamide solvent at the temperature of 20-25 ℃, and a magnetic stirrer is adopted to stir for 12 hours, so that uniform and transparent electrospray solution is obtained.

And (3) performing electrostatic spraying on the electrically sprayed solution by adopting an electrostatic spraying device, and spraying the electrostatically sprayed solution onto the surface of the silicone oil paper on the flat plate receiving device, so that polyurethane microspheres are attached to the surface of the silicone oil paper substrate, and thus the high-adhesion quasi-superhydrophobic material is obtained. Wherein the parameters of electrostatic spraying are set as follows: the inner diameter of the needle is 0.34mm, the voltage is 16kV, the propelling speed is 0.4mL/h, the propelling quantity is 1.2mL, the temperature is 25 ℃, the relative humidity is 65%, the distance between the flat plate receiving device and the needle (receiving distance) is 15cm, and the receiving surface of the flat plate receiving device is covered with silicone oil paper.

The high-adhesion quasi-superhydrophobic material prepared in example 1-2 was subjected to performance testing and analysis:

referring to the attached figure 1, it can be seen from the SEM image of the high adhesion quasi-superhydrophobic material in example 1 that: the polyurethane microspheres on the surface of the silicone oil paper are relatively dense, and the gaps among the microspheres are relatively small.

Referring to the attached FIG. 2, the particle size distribution diagram of the polyurethane microspheres in the high-adhesion quasi-superhydrophobic material in example 1 can be seen: the average particle size of the polyurethane microspheres was 1.4 μm, and the aspect ratio was calculated to be 1.2 by the formula Ar ═ a/b, where a is the longer side of the microspheres and b is the shorter side of the microspheres.

When the particle size of the polyurethane microspheres is too large, gaps among the polyurethane microspheres are increased, contact between water drops and a receiving device is increased, and the contact angle is reduced. When the aspect ratio of the polyurethane microspheres is too high, the appearance of the polyurethane microspheres becomes spindle-shaped, and gaps are increased, so that the contact angle is reduced.

Referring to the attached figure 3, a contact angle of the high-adhesion quasi-superhydrophobic material in example 1 is 145.1 degrees as measured by a contact angle measuring instrument DSA100, and when the contact angle is measured, a water drop 2 is dropped on the surface of the high-adhesion quasi-superhydrophobic material 1, and the specification of the high-adhesion quasi-superhydrophobic material 1 is 40 × 10 mm. Each sample was tested 3 times and the contact angle was averaged.

Referring to fig. 4, it can be seen from the SEM image of the highly adhesive quasi-superhydrophobic material in example 2 that: the polyurethane microspheres on the surface of the silicone oil paper are relatively dense, and the gaps among the microspheres are relatively small.

Referring to FIG. 5, the particle size distribution diagram of the polyurethane microspheres in the high-adhesion quasi-superhydrophobic material in example 2 can be seen: the average particle size of the polyurethane microspheres was 1.4 μm, and the aspect ratio was calculated to be 1.2 by the formula Ar ═ a/b, where a is the longer side of the microspheres and b is the shorter side of the microspheres.

Referring to the attached figure 6, a contact angle of the high-adhesion quasi-superhydrophobic material in example 2 is 140.3 degrees as measured by a contact angle measuring instrument DSA100, when the contact angle is measured, a water drop 2 is dropped on the surface of the high-adhesion quasi-superhydrophobic material 1, and the specification of the high-adhesion quasi-superhydrophobic material 1 is 40 × 10 mm. Each sample was tested 3 times and the contact angle was averaged.

Referring to FIG. 7, the IR spectrum of the high adhesion quasi-superhydrophobic material in example 1 was measured by a Nicolet-5700 IR spectrometer. 3343cm^-1The peak is the stretching vibration peak of the N-H bond in the carbamate group in the polyurethane microsphere, 1730cm^-1Peak at (2) is a stretching vibration peak of C ═ O bond in urethane group, 1520cm^-1The peak is the skeleton vibration peak of benzene ring in the polyurethane microsphere, 1167cm^-1The peak is the stretching vibration peak of the C-O-C bond, and the existence of the groups indicates that the high-adhesion quasi-super-hydrophobic material has certain hydrophobicity.

Referring to fig. 8, the water drops adhered to the surface of the quasi-superhydrophobic material in example 1 have different shapes at different angles. During testing, water drops 2 are dripped on the surface 1 of the high-adhesion quasi-super-hydrophobic material. As can be seen from fig. 8, during the rotation from 0 ° to 180 °, the water drop 2 does not drop from the surface of the high-adhesion quasi-superhydrophobic material, and the shape of the water drop 2 does not change much, which indicates that the high-adhesion quasi-superhydrophobic material has a certain adhesion to the water drop.

Referring to fig. 9, the water drop on the surface of the high-adhesion quasi-superhydrophobic material in example 1 has a shape diagram of the change of the water drop shape with time when the water drop is inverted by 180 degrees. During testing, water drops 2 are dripped on the surface of the high-adhesion quasi-super-hydrophobic material 1. As can be seen from fig. 9, the shape of the water droplet 2 did not change much within 10 minutes, but the contact angle between the water droplet 2 and the highly adhesive quasi-superhydrophobic material 1 changed slightly. From the beginning of inversion, the contact angle of water droplet 2 dropped by 14 ° after 10 minutes. At 20 minutes, the shape of drop 2 had changed significantly and the contact angle had dropped significantly. This also shows that the highly adherent quasi-superhydrophobic material 1 in example 1 has some adhesion to the water droplets 2.

Referring to fig. 10, the water drop adhered to the surface of the quasi-superhydrophobic material in example 2 has a shape diagram of the change of the water drop shape with time when the water drop is inverted by 180 °. During testing, water drops 2 are dripped on the surface of the high-adhesion quasi-super-hydrophobic material 1. As can be seen from fig. 10, the shape of the water droplet 2 did not change much within 10 minutes, but the contact angle between the water droplet 2 and the highly adhesive quasi-superhydrophobic material 1 changed slightly. From the beginning of inversion, the contact angle of water droplet 2 dropped by 10 ° after the lapse of 10 minutes. At 20 minutes, the shape of drop 2 had changed significantly and the contact angle had dropped significantly. This also shows that the highly adherent quasi-superhydrophobic material 1 of example 2 has some adhesion to the water droplets 2.

Referring to fig. 11, a graph of contact angles of a highly adherent quasi-superhydrophobic material and a water droplet with time in example 1. During testing, water drops are dripped on the surface of the high-adhesion quasi-super-hydrophobic material, and the specification of the high-adhesion quasi-super-hydrophobic material is 40 multiplied by 10 mm. It can be seen from fig. 11 that the contact angles of the high-adhesion quasi-superhydrophobic material and the water drop are not obviously changed with the time, and the contact angle can still be maintained at 130 degrees after 30 minutes, which shows that the prepared high-adhesion quasi-superhydrophobic material has certain durability to the water drop 2.

In the invention, when the electrically sprayed solution is subjected to electrostatic spraying, the concentration of polyurethane in the electrically sprayed solution is lower, so that single macromolecular chains of the polyurethane are isolated and do not overlap, and the viscous resistance is small. When voltage is applied, Ruili instability can occur, the charge force is greater than viscous resistance, jet flow is broken, the jet flow shrinks into balls under the action of surface tension to form a microsphere structure, and finally polyurethane microspheres are formed on the silicone oil paper base material of the flat plate receiving device.

The principle and the implementation mode of the invention are explained by applying specific embodiments in the invention, and the description of the embodiments is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.