阅读说明：本技术 一种用于克服流体瑞利不稳定行为的结构纤维及应用 (Structural fiber for overcoming Rayleigh unstable behavior of fluid and application ) 是由 刘欢 吕聪 王鹏伟 江雷 于 2020-04-08 设计创作，主要内容包括：本发明公开了一种用于克服流体瑞利不稳定行为的结构纤维及应用,针对现有的圆柱状纤维上的液体涂层由于流体的瑞利不稳定行为容易形成纺锤结,很难在圆柱状纤维上实现均匀、平滑的液膜的问题提出。本发明提供的上述结构纤维是在单根圆柱状纤维的基础上并排引入尺寸相同且表面能相同的圆柱状纤维,得到非圆形横截面的结构纤维。与传统的单根圆柱状纤维相比,本发明提供的上述结构纤维具有简单、高效、低成本且能够克服流体在纤维上因瑞利不稳定现象而导致的液体不均匀平滑铺展的优势。利用本发明提供的上述结构纤维可以实现液体在纤维上的平滑均匀铺展成膜,从而可以将其应用在纤维涂覆、微流体运输及微型检测等方面。(The invention discloses a structural fiber for overcoming the Rayleigh unstable behavior of fluid and application thereof, and aims to solve the problem that a liquid coating on the existing cylindrical fiber is difficult to realize a uniform and smooth liquid film on the cylindrical fiber because a spindle knot is easily formed due to the Rayleigh unstable behavior of the fluid. The structural fiber provided by the invention is characterized in that cylindrical fibers with the same size and surface energy are introduced side by side on the basis of a single cylindrical fiber to obtain the structural fiber with a non-circular cross section. Compared with the traditional single cylindrical fiber, the structural fiber provided by the invention has the advantages of simplicity, high efficiency, low cost and capability of overcoming the defect of uneven and smooth spreading of liquid on the fiber due to the Rayleigh instability phenomenon of the fluid. The fiber with the structure provided by the invention can realize smooth and uniform spreading and film forming of liquid on the fiber, so that the fiber can be applied to the aspects of fiber coating, microfluid transportation, micro detection and the like.)

1. A structural fiber for overcoming rayleigh instability behavior of a fluid, characterized by:

the structural fibers comprise at least two cylindrical fibers which are arranged side by side and have the same size and the same surface energy, and the cross sections of the structural fibers are at least two circles which are arranged side by side and have the same size.

2. The structural fiber for overcoming rayleigh instability behavior in fluids according to claim 1, wherein the material of each cylindrical fiber in the structural fiber is the same; or at least two cylindrical fibers in the structural fibers are made of different materials, the surface energy of each cylindrical fiber is the same, and the surface energy of the cylindrical fibers made of different materials is modified through surface chemical modification.

3. A structural fiber for overcoming fluid rayleigh instability behavior as in claim 1 wherein the material of the cylindrical fiber is any one of polymer, inorganic oxide and metal.

4. The structural fiber for overcoming rayleigh instability behavior in fluids according to claim 1, wherein the length of the structural fiber ranges from 0.01mm to 100 m.

5. The structural fiber for overcoming rayleigh instability behavior in fluids according to claim 1 wherein each cylindrical fiber has a diameter in the range of 10nm to 100 cm.

6. The structural fiber for overcoming rayleigh instability behavior in fluids according to claim 1 wherein the surface of the structural fiber is a smooth surface.

7. The structural fiber for overcoming rayleigh instability behavior in fluids according to claim 1, wherein the structural fiber is an integrally formed structure; alternatively, the first and second electrodes may be,

the structural fiber is formed by splicing at least two cylindrical fibers side by side; and every two adjacent cylindrical fibers are bonded through an adhesive, or are chemically cross-linked and fixed through interfacial polymerization.

8. A structural fibre for overcoming rayleigh instability behaviour in fluids according to any of claims 1-7 characterised in that the number of cylindrical fibres is 2 or 3 or 4.

9. A test method for overcoming the Rayleigh instability behavior of a fluid by a structural fiber, which is the structural fiber for overcoming the Rayleigh instability behavior of the fluid according to any one of claims 1 to 8, comprises the following steps:

s1: pulling the structural fiber out of the liquid pool at a constant speed along the long axis direction of the fiber;

s2: standing the structural fiber after passing through the liquid pool, observing the spreading behavior of the liquid on the structural fiber, recording the time of the liquid aggregating into spindle knots, and testing the capability of the structural fiber for overcoming the Rayleigh instability of the fluid according to the time of the liquid aggregating into the spindle knots;

s3: returning to step S1, repeating steps S1 and S2, changing only the drawing speed of the structural fiber;

s4: returning to step S1, steps S1 and S2 are repeatedly performed to replace only the liquid in the liquid pool.

10. Use of a structural fibre according to any one of claims 1 to 8 for overcoming rayleigh instability behaviour of a fluid for fibre coating, microfluidic transport and micro-detection.

Technical Field

The invention relates to the technical field of functional materials, in particular to a structural fiber for overcoming the Rayleigh unstable behavior of fluid and application thereof.

Background

The liquid column always breaks down into spherical droplets to achieve surface energy minimization, a common phenomenon known as placato-Rayleigh Instability (also known as capillary Instability). This uneven liquid film caused by the plalto-rayleigh instability is not conducive to the production of composite fibers by fluid coating, electrospinning and microfluidics.

Previous studies have shown that space limitations can inhibit rayleigh instability, but it is currently mainly operated in semi-closed systems under certain extreme conditions (e.g. high temperature), which is difficult to apply to various liquids and open systems. The methods for overcoming rayleigh instability of fluid have been mainly achieved by surfactant method, UV/high temperature curing treatment or by some specific chemical reaction, however, these methods are limited by materials and liquid components and also cause waste of resources and environmental pollution.

Therefore, how to provide a simple and general method for overcoming rayleigh instability under mild conditions is a problem that researchers in the field need to solve urgently.

Disclosure of Invention

In view of the above, the present invention provides a structural fiber for overcoming rayleigh instability of fluid and an application thereof, so as to solve the problems that liquid on the existing cylindrical fiber is easy to form spindle knots, and it is difficult to maintain a uniform and smooth liquid film on the fiber.

Accordingly, the present invention provides a structural fiber for overcoming rayleigh instability behavior of a fluid:

the structural fibers comprise at least two cylindrical fibers which are arranged side by side and have the same size and the same surface energy, and the cross sections of the structural fibers are at least two circles which are arranged side by side and have the same size.

In one possible implementation, in the structural fiber for overcoming rayleigh instability behavior of a fluid provided by the present invention, the material of each cylindrical fiber in the structural fiber is the same; or at least two cylindrical fibers in the structural fibers are made of different materials, the surface energy of each cylindrical fiber is the same, and the surface energy of the cylindrical fibers made of different materials is modified through surface chemical modification.

In a possible implementation manner, in the structural fiber for overcoming the rayleigh instability behavior of the fluid provided by the present invention, the material of the cylindrical fiber is any one of a polymer, an inorganic oxide and a metal.

In one possible implementation, in the structural fiber for overcoming rayleigh instability behavior of a fluid provided by the present invention, the length of the structural fiber ranges from 0.01mm to 100 m.

In one possible implementation, in the structural fiber for overcoming rayleigh instability behavior of a fluid provided by the present invention, each cylindrical fiber has a diameter ranging from 10nm to 100 cm.

In one possible implementation, in the structural fiber for overcoming rayleigh instability behavior of a fluid as described above, provided by the present invention, the surface of the structural fiber is a smooth surface.

In one possible implementation, in the structural fiber for overcoming rayleigh instability behavior of a fluid provided by the present invention, the structural fiber is an integrally formed structure; alternatively, the first and second electrodes may be,

the structural fiber is formed by splicing at least two cylindrical fibers side by side; and every two adjacent cylindrical fibers are bonded through an adhesive, or are chemically cross-linked and fixed through interfacial polymerization.

In a possible implementation manner, in the structural fiber for overcoming the rayleigh instability behavior of the fluid provided by the present invention, the number of the cylindrical fibers is 2 or 3 or 4.

The invention also provides a method for testing the structural fiber to overcome the Rayleigh unstable behavior of the fluid, wherein the structural fiber is the structural fiber for overcoming the Rayleigh unstable behavior of the fluid, and the method comprises the following steps:

s1: pulling the structural fiber out of the liquid pool at a constant speed along the long axis direction of the fiber;

s2: standing the structural fiber after passing through the liquid pool, observing the spreading behavior of the liquid on the structural fiber, recording the time of the liquid aggregating into spindle knots, and testing the capability of the structural fiber for overcoming the Rayleigh instability of the fluid according to the time of the liquid aggregating into the spindle knots;

s3: returning to step S1, repeating steps S1 and S2, changing only the drawing speed of the structural fiber;

s4: returning to step S1, steps S1 and S2 are repeatedly performed to replace only the liquid in the liquid pool.

The invention also provides the application of the structural fiber for overcoming the Rayleigh instability behavior of the fluid, and the structural fiber is used for realizing fiber coating, microfluid transportation and micro detection.

The structural fiber for overcoming the rayleigh unstable behavior of the fluid and the application thereof provided by the invention are provided aiming at the problems that the liquid coating on the existing cylindrical fiber is easy to form spindle knots due to the rayleigh unstable behavior of the fluid and is difficult to realize uniform and smooth liquid film on the cylindrical fiber. The structural fiber provided by the invention is obtained by introducing cylindrical fibers with the same size and surface energy side by side on the basis of a single cylindrical fiber, and is a structural fiber with a non-circular cross section, such as a structural fiber obtained by splicing two cylindrical fibers, three cylindrical fibers or four cylindrical fibers side by side. Compared with the traditional single cylindrical fiber, the structural fiber provided by the invention has the advantages of simplicity, high efficiency, low cost and capability of overcoming the defect of uneven and smooth spreading of liquid on the fiber due to the Rayleigh instability phenomenon of the fluid. The fiber with the structure provided by the invention can realize smooth and uniform spreading and film forming of liquid on the fiber, so that the fiber can be applied to the aspects of fiber coating, microfluid transportation, micro detection and the like.

Drawings

FIG. 1 is a schematic structural diagram of a structural fiber for overcoming Rayleigh instability of a fluid according to the present invention;

FIG. 2 is a schematic cross-sectional view of the structural fiber shown in FIG. 1;

FIG. 3 is a schematic structural view of a single conventional cylindrical fiber;

FIG. 4 is a schematic cross-sectional view of a single cylindrical fiber shown in FIG. 3;

FIG. 5 is a schematic illustration of the spreading of a liquid over the structural fiber shown in FIG. 1;

FIG. 6 is a schematic cross-sectional view of the spreading of a liquid over the structural fiber shown in FIG. 1;

FIG. 7 is a schematic illustration of the spreading of a liquid over a single cylindrical fiber shown in FIG. 3;

FIG. 8 is a schematic cross-sectional view of the spreading of liquid over the single cylindrical fiber shown in FIG. 3;

FIG. 9 is a flow chart of a method for testing the structural fiber to overcome Rayleigh instability of a fluid according to the present invention;

FIG. 10 is an optical diagram of the liquid spreading of two parallel fibers and a single cylindrical fiber in example 1 of the present invention.

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 illustrative and are not intended to limit the present invention.

The invention provides a structural fiber for overcoming the Rayleigh unstable behavior of a fluid, which comprises the following components in percentage by weight:

as shown in fig. 1, the structural fiber includes at least two cylindrical fibers with the same size and surface energy side by side, and as shown in fig. 2, the cross section of the structural fiber is at least two circles with the same size and side by side.

Both figures 1 and 2 exemplify structural fibers comprising two cylindrical fibers side by side. Specifically, the dimensions of the respective cylindrical fibers in the structural fibers are the same, i.e., the diameters of the cross sections of the respective cylindrical fibers are the same, and the lengths of the respective cylindrical fibers are the same.

In practical implementation, in the structural fiber for overcoming the rayleigh instability behavior of the fluid provided by the present invention, the number of the cylindrical fibers may be 2, that is, the structural fiber may include two cylindrical fibers with the same size and the same surface energy side by side (as shown in fig. 1), and the cross section of the structural fiber is two circles with the same size and arranged side by side (as shown in fig. 2); or, the number of the cylindrical fibers may also be 3, that is, the structural fibers may also include three side-by-side cylindrical fibers with the same size and surface energy, and the cross section of the structural fibers is three circles with the same size and arranged side by side; alternatively, the number of the cylindrical fibers may also be 4, that is, the structural fiber may also include four side-by-side cylindrical fibers with the same size and the same surface energy, and the cross section of the structural fiber is four circles with the same size and arranged side by side, which is not limited herein. Whereas the prior art single cylindrical fiber is shown in fig. 3 and has a circular cross-section as shown in fig. 4.

Structural fibers as shown in fig. 1 and 2 and a single cylindrical fiber as shown in fig. 3 and 4 were tested to overcome the rayleigh instability behavior of the fluid. After the structural fiber is pulled out from the liquid pool at a constant speed, the liquid is smoothly and uniformly spread on the surface of the structural fiber to form a film, as shown in figure 5, and the cross section of the structural fiber is as shown in figure 6, so that the Rayleigh unstable behavior of the fluid can be effectively overcome. After the single cylindrical fiber is pulled out from the liquid pool at a constant speed, the liquid can be condensed into spindle knots on the single cylindrical fiber due to the surface energy, as shown in fig. 7, and the cross section is as shown in fig. 8.

In practical implementation, in the structural fiber for overcoming the rayleigh instability behavior of the fluid provided by the present invention, the material of each cylindrical fiber in the structural fiber may be the same; or, the structural fibers may have cylindrical fibers with different materials, that is, at least two cylindrical fibers in the structural fibers are different in material, and it is only necessary to ensure that the surface energy of each cylindrical fiber is the same, and the surface energy of the cylindrical fibers with different materials may be modified by surface chemical modification.

In particular embodiments, the invention provides the above-described method for overcoming rayleigh instability in a fluidIn the structural fibers, the material of the cylindrical fibers may be a polymer, for example, polyhexamethylene adipamide (PA 66); alternatively, the material of the cylindrical fiber may be an inorganic oxide, for example, Silica (SiO)₂) Zinc oxide (ZnO)₂) Titanium oxide (TiO)₂) Aluminum oxide (Al)₂O₃) Etc.; alternatively, the material of the cylindrical fibers may also be a metal, such as copper, platinum, iron, aluminum, or the like; and are not limited herein.

In specific implementation, in the structural fiber for overcoming the rayleigh instability of the fluid provided by the present invention, if the length of the structural fiber is too long, the fiber is easily broken during the manufacturing process of the structural fiber, and if the length of the structural fiber is too short, the problem that the observation of the liquid movement is not accurate enough occurs, so that the length of the structural fiber can be controlled within the range of 0.01mm to 100m in order to avoid the above problems.

In practical implementation, in the structural fiber for overcoming the rayleigh instability of the fluid provided by the present invention, if each cylindrical fiber is too thin, the fiber is likely to be broken during the manufacturing process of the structural fiber, and if each cylindrical fiber is too thick, the amount of liquid required to cover the entire fiber is too large, so that the diameter of each cylindrical fiber in the structural fiber can be controlled within a range of 10nm to 100cm in order to avoid the above problems.

In practice, the present invention provides the structural fiber for overcoming rayleigh instability of fluid, wherein the size of the structural fiber is mainly determined by the number of cylindrical fibers arranged in parallel and side by side. The more the number of the cylindrical fibers is, the smaller the eccentricity of the cross section formed after the surface of the structural fiber is wrapped with liquid is, and the capability of the structural fiber to overcome the fluid Rayleigh instability is influenced. In practical applications, the number of cylindrical fibers included in the structural fibers needs to be designed according to the length of the structural fibers.

In practical implementation, in the structural fiber for overcoming the rayleigh instability behavior of the fluid provided by the present invention, the surface of the structural fiber may be a smooth surface, and the structural fiber with the smooth surface can also overcome the rayleigh instability behavior of the fluid, that is, the rayleigh instability behavior of the fluid of the structural fiber is overcome not by the surface roughness of the fiber but by the structure of the structural fiber itself. Of course, the surface of the structural fiber may also be a rough surface, and the ability to overcome the rayleigh instability of the fluid may be further enhanced, which is not limited herein.

In specific implementation, in the structural fiber for overcoming the rayleigh instability of the fluid provided by the present invention, the structural fiber may be an integrally formed structure, that is, all cylindrical fibers in the structural fiber are integrally formed structures; or the structural fiber can also be formed by splicing at least two cylindrical fibers side by side; and are not limited herein. Specifically, the splicing manner of the cylindrical fibers in the structural fibers may be as follows: every two adjacent cylindrical fibers can be bonded through an adhesive; alternatively, every two adjacent cylindrical fibers may be chemically cross-linked and fixed by interfacial polymerization, which is not limited herein. Specifically, the interfacial polymerization may be light-induced interfacial polymerization, or the interfacial polymerization may also be heat-induced interfacial polymerization, or the interfacial polymerization may also be solvent-induced interfacial polymerization, which is not limited herein.

Based on the same inventive concept, the invention further provides a method for testing the structural fiber to overcome the rayleigh unstable behavior of the fluid, and the structural fiber is the structural fiber for overcoming the rayleigh unstable behavior of the fluid, as shown in fig. 9, and the method comprises the following steps:

s1: pulling the structural fiber out of the liquid pool at a constant speed along the long axis direction of the fiber;

specifically, after the structural fiber is straightened, one end of the structural fiber can be pulled out of the liquid pool, and the pulling speed can be regulated and controlled according to actual conditions and different liquids; it should be noted that, because the fibers have certain elasticity, the fibers cannot be straightened by excessive force to prevent the fibers from deforming; the liquid in the liquid pool may be water, or may also be a solution of silicone oil, chloroform, an organic solvent, and the like, which is not limited herein;

s2: standing the structural fiber after passing through the liquid pool, observing the spreading behavior of the liquid on the structural fiber, recording the time of the liquid aggregating into spindle knots, and testing the capability of the structural fiber for overcoming the Rayleigh instability of the fluid according to the time of the liquid aggregating into the spindle knots;

specifically, the structural fiber still needs to be kept in a straight state after being pulled out of the liquid pool, and the standing time can be freely set according to actual conditions and selected liquid; the spreading behavior of the liquid is that whether the liquid has Rayleigh instability phenomenon or not;

s3: returning to step S1, repeating steps S1 and S2, changing only the drawing speed of the structural fiber;

specifically, the pulling speed of the structural fiber can be designed as a variable, and the capability of the structural fiber for overcoming the Rayleigh instability of the fluid at different pulling speeds is tested;

s4: returning to step S1, repeating steps S1 and S2 to replace only the liquid in the liquid pool;

in particular, the type of liquid can be designed as a variable to test the ability of the structural fiber to overcome the rayleigh instability of the fluid at different liquid viscosities.

The method for testing the structural fiber to overcome the Rayleigh unstable behavior of the fluid has the advantages of low cost, easily obtained raw materials, simple process and the like.

The following provides a detailed description of the specific implementation of the method for testing the structural fiber to overcome the rayleigh instability of the fluid provided by the present invention.