A method for preparing electroluminescent fiber by integrated spinning

Abstract

The present invention provides a method for preparing an electroluminescent fiber by one-piece spinning, comprising: step S1, dissolving a polymer A and a luminescent active material in an organic solvent A to prepare a polymer spinning solution A loaded with a luminescent active material; step S2, dissolving a polymer B in an organic solvent B, optionally adding a conductive material, to prepare a polymer spinning solution B loaded with a conductive material; step S3, polymer spinning solution A and polymer spinning solution B are co-extruded through a microfluidic spinning chip or a sandwich spinneret to form a sandwich primary fiber of "conductive material-luminescent material-conductive material", and the primary fiber is cured, stretched and conductively modified to obtain a molded luminescent fiber; step S4, finally coating the outside of the molded fiber with a transparent insulating polymer for encapsulation to obtain an electroluminescent fiber. The method of the present invention is highly controllable and repeatable, adopts a sandwich structure, has a stable fiber structure, and has a good luminescent effect.

Description

Technical Field

[0001] The invention relates to the technical field of functional materials, and in particular to a method for preparing electroluminescent fibers by integral spinning. Background Art

[0002] Electroluminescent fiber is a new type of optoelectronic material with the characteristics of high brightness, low power, long life and flexibility. It can be widely used in information display, optical communication, biomedicine, security and anti-counterfeiting and other fields. The research and application of electroluminescent fibers have important scientific significance and application value. According to the different luminescent materials and luminescent principles, the electroluminescent system can be roughly divided into polymer electroluminescence (PLED), organic electroluminescence (OLED), quantum dot electroluminescence (QLED) and alternating current electroluminescence (ACEL). The application of electroluminescent devices of different luminescent systems is different. Among them, the inorganic alternating current electroluminescent system has significant advantages in the preparation of flexible electroluminescent devices because of its advantages such as easy storage of luminescent materials, simple preparation process and low cost.

[0003] The basic structure of a flexible AC electroluminescent device is to sandwich a luminescent layer and a dielectric layer between two electrodes attached to a substrate. This structure is equivalent to three capacitors connected in series in an AC circuit. Among them, the luminescent layer is the main functional layer, which is formed by a mixture of ZnS particles doped with metal particles and an adhesive with certain dielectric properties; the dielectric layer blocks the passage of charges and plays a role in protecting the device, which can effectively avoid the phenomenon of the luminescent layer being broken down due to excessive field strength after power-on; the transparent electrode plays a conductive role and ensures that light passes smoothly without weakening the light intensity. Due to the basic structure of the flexible AC electroluminescent device, the preparation of flexible AC electroluminescent fibers mostly adopts the preparation method of multiple coatings of coaxial structure, and the inner electrode, luminescent layer, dielectric layer, outer electrode and encapsulation layer are assembled on the fiber surface in sequence to form the basic structure of the flexible AC electroluminescent device. As a result, the current preparation process of electroluminescent fibers is relatively complicated, and the high material cost and preparation cost limit its promotion in large-scale production and application.

[0004] Therefore, developing a new method for preparing electroluminescent fibers with high integration and plasticity is of great significance for achieving wider applications. Microfluidics is a unique method for preparing nanofibers with high controllability. The use of microfluidics to prepare electroluminescent nanofibers can achieve effective regulation at the fiber structure level, so that in a spinning system, through one-time spinning forming, the integrated preparation of the fiber structure of "conductive material-luminescent material-conductive material" can be achieved, solving the complex and cumbersome process problems caused by multiple coating and assembly in the current preparation process of flexible AC electroluminescent fiber devices. Summary of the invention

[0005] The present invention uses a microfluidic spinning method to spin electroluminescent fibers in one step, solving the shortcomings of complex, difficult and costly preparation of electroluminescent fibers. Through microfluidic wet spinning, the thickness of each component of the luminescent fiber can be accurately controlled, while avoiding multiple coating processes and eliminating the need for expensive conductive cores, greatly reducing costs.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for preparing electroluminescent fibers by integral spinning, comprising:

[0008] Step S1, dissolving polymer A and luminescent active material in organic solvent A to prepare polymer spinning solution A loaded with luminescent active material;

[0009] Step S2, dissolving polymer B in organic solvent B, and optionally adding a conductive material, to prepare a polymer spinning solution B loaded with a conductive material;

[0010] Step S3, polymer spinning solution A and polymer spinning solution B are co-extruded through a microfluidic spinning chip or a sandwich spinneret, and the component content and component structure in the fiber are controlled by controlling the propulsion speed of the two spinning solutions, wherein the propulsion speed of polymer A is 10-100 ml / min, and the speed of polymer B is 5-80 ml / min, and finally a sandwich primary fiber of "conductive material-luminescent material-conductive material" (BAB) is formed, and the primary fiber is cured, stretched and conductively modified to obtain a formed luminescent fiber;

[0011] Step S4, finally coating the outside of the molded fiber with a transparent insulating polymer for encapsulation to obtain an electroluminescent fiber;

[0012] Wherein organic solvent A and organic solvent B are selected from the same or different solvents;

[0013] The polymer A and the polymer B are selected from different polymers; the reason why the polymer A and the polymer B are selected from different polymers is that when the subsequent conductive treatment is performed, only when the two are different, only the polymer B component can be modified without modifying the polymer A, thereby not affecting the performance of the polymer A component;

[0014] The luminescent active material and the conductive material are different materials.

[0015] Optionally, in step S1, the specific process for preparing polymer spinning solution A is: firstly dissolving polymer A in organic solvent A to prepare spinning solution with a mass fraction of 1%-50%, and then dissolving luminescent active material into the spinning solution, with a mass fraction of luminescent active material of 0.1%-30%.

[0016] Optionally, in step S2, the specific process of the polymer spinning solution B is: firstly dissolving the polymer B in the organic solvent B to prepare a spinning solution with a mass fraction of 1%-50%, and then dissolving the conductive material into the spinning solution, with a mass fraction of the conductive material of 0.1%-30%.

[0017] Optionally, in step S1, polymer A is selected from at least one of polyacrylonitrile, sodium alginate, polyurethane, elastic silicone rubber, polylactic acid, polyester, and polyamide; the luminescent material is selected from at least one of ZnS:Cu (Cu doped ZnS), ZnS:Mn (Mn doped ZnS), ZnS:Cd (Cd doped ZnS), ZnS:A1 (A1 doped ZnS), and ZnS:Ag (Ag doped ZnS).

[0018] Optionally, in step S1, polymer B is selected from at least one of polyacrylonitrile, sodium alginate, polyurethane, elastic silicone rubber, polylactic acid, polyester, and polyamide; the conductive material is selected from at least one of conductive nanocarbon materials (such as carbon nanotubes, graphene, etc.), conductive hydrogels (ion conductive hydrogels such as salt ions, ionic liquids, polyelectrolytes, conductive polymer-based, carbon materials, MXene and metal-based electronic conductive hydrogels), conductive polymers (polypyrrole, polythiophene, polystyrene, polyaniline, etc.), metals (silver, copper, gold, aluminum, iron, titanium, etc.), and metal oxides (copper oxide, nickel oxide, etc.).

[0019] Optionally, in steps S1 and S2, the organic solvent A and the organic solvent B are selected from at least one of ethanol, acetone, dimethyl sulfoxide, and N,N-dimethylformamide.

[0020] Optionally, in step S3, the microfluidic spinning chip has two channels or three channels, wherein the outer channel is used to pass polymer spinning solution B, and the middle channel is used to pass polymer spinning solution A, the channel cross-section is square or circular, the inner diameter of the outer channel is 0.1-3 mm, and the inner diameter of the middle channel is 30-500 μm; the sandwich spinneret needle is a composite structure, a thicker channel has a thinner channel on each side, the thicker channel is used to pass polymer spinning solution A, and the two thinner channels are used to pass polymer spinning solution B, the thicker channel has an inner diameter of 0.1-5 mm, and the thinner channel has an inner diameter of 0.05-1 mm. Among them, the thicker channel is used to pass spinning solution A, so that the fiber body of the luminous part is large, so that the luminous area is large after power is turned on, and the spinning solution B is mainly the electrode part. If it is too thick, it will affect the light dispersion of the luminous part. Both the microfluidic chip and the sandwich needle can realize the design and preparation of the sandwich structure fiber in the present invention. Among them, microfluidic chips have the following advantages over sandwich needles: 1) they can control the liquid speed and flow rate; 2) they can spin out a variety of different fiber structures.

[0021] Optionally, in step S3, the step of stretching and solidifying the spun fibers includes: drawing out the spun fibers and guiding them to a stretching mechanism consisting of a first stretching roller, a second stretching roller, and a lead-out roller, and then entering the conductive modification solution again through the lead-out roller for modification. The conductive modification step includes: introducing the spun fibers into an impregnation solution containing a conductive material for conductive modification.

[0022] Furthermore, the present invention provides an electroluminescent fiber.

[0023] Furthermore, the electroluminescent fiber of the present invention can be used in the fields of lighting and display.

[0024] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0025] 1) The prepared electroluminescent fiber has good luminescence performance and stability. The flexibility of the fiber is improved by using polymers (A, B). Due to the application of microfluidics, the structural thickness of the luminescent fiber can be precisely controlled, ultimately making the fiber emit light stably.

[0026] 2) The preparation method is simple and low-cost. The luminescent fiber can be prepared with a homemade microfluidic chip and a cheap polymer substrate, avoiding the troublesome process of multiple coatings and integrated molding, which greatly reduces the cost.

[0027] The method of the present invention is highly controllable and repeatable, adopts a sandwich structure, has a stable fiber structure, and has a good luminous effect. In addition, the luminescent material is composed of a mixed solution of doped ZnS and polymer materials, has high luminous efficiency and stability, and the prepared electroluminescent fiber can be applied to lighting, display and other fields, and has good practical application value and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a digital photo of the two-channel microfluidic spinning chip used in the present invention.

[0030] Figure 2 This is a digital photo of the sandwich spinneret needle used in the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] Step S1, dissolving a spinning solution with a polyurethane configuration mass fraction of 30% in an organic solvent, and adding a luminescent active material ZnS:Cu to the spinning solution to prepare a polyurethane spinning solution A loaded with a luminescent active material mass fraction of 30%;

[0034] Step S2, dissolving elastic silicone rubber PDMS in an organic solvent dimethyl sulfoxide to prepare a spinning solution with a mass fraction of 50%, adding conductive material silver nanowires to the spinning solution to prepare a polymer spinning solution B with a mass fraction of 20% loaded conductive material;

[0035] Step S3, polymer spinning solution A and polymer spinning solution B are co-extruded through a two-channel microfluidic spinning chip, and the component content and component structure in the fiber are controlled by controlling the propulsion speed of the two spinning solutions, wherein the propulsion speed of polymer A is 70 ml / min, and the speed of polymer B is 50 ml / min, and finally a sandwich primary fiber of "conductive material-luminescent material-conductive material" (BAB) is formed, and the primary fiber is cured, stretched and conductively modified to obtain a formed luminescent fiber;

[0036] Step S4: Finally, the outer surface of the molded fiber is coated with transparent silicone rubber for encapsulation to obtain an electroluminescent fiber. The fiber has good flexibility and can be woven with ordinary yarn. The luminous brightness can reach 50cd / m at an AC voltage of 3V. 2 .

[0037] Example 2

[0038] Step S1, dissolving a spinning solution with a polyurethane configuration mass fraction of 30% in an organic solvent, and adding a luminescent active material ZnS:Cu to the spinning solution to prepare a polyurethane spinning solution A loaded with a luminescent active material mass fraction of 30%;

[0039] Step S2, dissolving polyacrylonitrile in an organic solvent N,N-dimethylformamide to prepare a polymer spinning solution B with a mass fraction of 10%;

[0040] Step S3, polymer spinning solution A and polymer spinning solution B are co-extruded through a two-channel microfluidic spinning chip, and the component content and component structure in the fiber are controlled by controlling the propulsion speed of the two spinning solutions, wherein the propulsion speed of polymer A is 60 ml / min, and the speed of polymer B is 45 ml / min, and finally a sandwich primary fiber of "conductive material-luminescent material-conductive material" (BAB) is formed, and the primary fiber is cured and drawn, and the polyacrylonitrile component in the sandwich fiber is chemically complexed and conductively modified with 5% by mass copper sulfate and 6% by mass sodium thiosulfate solution, and finally a molded luminescent fiber is obtained;

[0041] Step S4: The outer surface of the molded fiber is coated with transparent silicone rubber for encapsulation to obtain an electroluminescent fiber. The fiber has good flexibility and can be woven with ordinary yarn. The luminous brightness can reach 46cd / m at an AC voltage of 3V. 2 .

[0042] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing electroluminescent fibers by integral spinning, characterized in that: include: Step S1, dissolving polymer A and luminescent active material in organic solvent A to prepare polymer spinning solution A loaded with luminescent active material; Step S2, dissolving polymer B in organic solvent B, and adding conductive material to prepare a polymer spinning solution B loaded with conductive material; Step S3, polymer spinning solution A and polymer spinning solution B are co-extruded through a microfluidic spinning chip, wherein the advancement speed of polymer A is 10-100 ml / min, and the advancement speed of polymer B is 5-80 ml / min, and finally a sandwich primary fiber of "conductive material-luminescent material-conductive material" is formed by regulation, and the primary fiber is cured, stretched and conductively modified to obtain a formed luminescent fiber; Step S4, finally coating the outside of the molded fiber with a transparent insulating polymer for encapsulation to obtain an electroluminescent fiber; Wherein organic solvent A and organic solvent B are selected from the same or different solvents; Polymer A and polymer B are selected from different polymers; The luminescent active material and the conductive material are different materials; In step S3, the microfluidic spinning chip has two channels or three channels, wherein the outer channel is used to pass the polymer spinning solution B, and the middle channel is used to pass the polymer spinning solution A. The channel cross-section is square or circular, the inner diameter of the outer channel is 0.1~3mm, and the inner diameter of the middle channel is 30~500μm.

2. The method according to claim 1, characterized in that In step S1, the specific process of preparing polymer spinning solution A is: firstly dissolving polymer A in organic solvent A to prepare spinning solution with a mass fraction of 1%-50%, and then dissolving luminescent active material into the spinning solution, with the mass fraction of luminescent active material being 0.1%-30%.

3. The method according to claim 1, characterized in that In step S2, the specific process of the polymer spinning solution B is: firstly dissolving the polymer B in the organic solvent B to prepare a spinning solution with a mass fraction of 1%-50%, and then dissolving the conductive material into the above spinning solution, with the mass fraction of the conductive material being 0.1%-30%.

4. The method according to claim 1, characterized in that: In step S1, polymer A is selected from at least one of polyacrylonitrile, sodium alginate, polyurethane, elastic silicone rubber, polylactic acid, polyester, and polyamide; and the luminescent material is selected from one or more of ZnS:Cu, ZnS:Mn, ZnS:Cd, ZnS:Al, and ZnS:Ag.

5. The method according to claim 1, characterized in that: In step S1, polymer B is selected from at least one of polyacrylonitrile, sodium alginate, polyurethane, elastic silicone rubber, polylactic acid, polyester, and polyamide; and the conductive material is selected from at least one of conductive nanocarbon materials, conductive hydrogels, conductive polymers, metals, and metal oxides.

6. The method according to claim 1, characterized in that In steps S1 and S2, the organic solvent A and the organic solvent B are selected from at least one of ethanol, acetone, dimethyl sulfoxide, and N,N-dimethylformamide.

7. The method according to claim 1, characterized in that In step S3, the step of stretching and solidifying the spun fibers includes: drawing out the spun fibers and guiding them to a stretching mechanism consisting of a first stretching roller, a second stretching roller, and a lead-out roller, and then entering the conductive modification solution again through the lead-out roller for modification. The conductive modification step includes: introducing the spun fibers into an impregnation solution containing a conductive material for conductive modification.

8. An electroluminescent fiber prepared according to the method according to any one of claims 1 to 7.

9. Application of the electroluminescent fiber according to claim 8 in the fields of lighting and display.

Images