ELECTRONIC-INK-BASED COLORFUL PATTERNED COLOR-CHANGING FABRICS AND PREPARATION METHODS THEREOF

Abstract

Electronic-ink-based colorful patterned color-changing fabrics and preparation methods thereof are provided. The fabric includes a conductive fabric microstrip formed by weaving using conductive yarn and insulating yarn. The conductive yarn forms a conductive region, and the insulating yarn form an insulating region. An electronic ink microencapsule layer is arranged on the conductive region. A flexible transparent conductive layer is arranged on the electronic ink microencapsule layer. A transparent polymer layer is arranged on the flexible transparent conductive layer. A surface layer of the microstrip is a conductive layer, and a bottom layer of the microstrip is an insulating layer. An electrophoretic color-changing microencapsule, a conductive one-dimensional nanomaterial, and a transparent polymer are uniformly coated on a surface of the microstrip, and a voltage output by a drive circuit is respectively applied to the conductive microstrip and the transparent conductive layer to achieve selective flip and color rendering of centimeter-scale micro-region on the surface of the microstrip. Upper and lower electrodes are connected with a control circuit to achieve centimeter-scale pixel control and large-size graphic display and make a conductive-fabric-substrate-based foldable, high-environmental tolerant low-cost large-area color display and adaptive visible light camouflage fabric.

Claims

1. A method for preparing an electronic-ink-based colorful patterned color-changing fabric, the electronic-ink-based colorful patterned color-changing fabric including a conductive fabric microstrip formed by weaving using conductive yarn and insulating yarn, the conductive yarn forming a conductive region, the insulating yarn forming an insulating region, an electronic ink microencapsule layer being arranged on the conductive region for image display, the electronic ink microencapsule layer including an electronic ink microencapsule slurry and an adhesive, a flexible transparent conductive layer being arranged on the electronic ink microencapsule layer for providing an electrophoretic color rendering voltage, the flexible transparent conductive layer including a single-walled carbon nanotube and a silver nanowire slurry, a transparent polymer layer being arranged on the conductive fabric microstrip for encapsulation, wherein the method comprises: step 1, weaving the conductive yarn and the insulating yarn into the conductive fabric microstrip using a double-layer warp knitting process, the conductive yarn and the insulating yarn constructing the conductive region and the insulating region, respectively, on the fabric microstrip; step 2, uniformly coating the electronic ink microencapsule slurry mixed with the adhesive to the conductive region and forming the electronic ink microencapsule layer after curing; step 3, coating the silver nanowire slurry on a surface of the electronic ink microencapsule layer and drying, coating a single-walled carbon nanotube aqueous solution on the dried surface of the electronic ink microencapsule layer to form the flexible transparent conductive layer after being blow-dried, and sewing the conductive yarn in a direction perpendicular to a length of the conductive fabric microstrip, so that the conductive yarn conduct with the flexible transparent conductive layer and are fixed to the conductive fabric microstrip; step 4, cutting and disconnecting the conductive region with a low-energy Yttrium Aluminum Garnet (YAG) laser to form independent display pixels; step 5, uniformly coating a transparent polymer slurry on a surface of the conductive fabric microstrip to form the transparent polymer layer; step 6, applying a voltage output from a drive circuit to the conductive region and the flexible transparent conductive layer respectively to flip color rendering of a discrete single pixel for by electrophoresis; and step 7, weaving or splicing the conductive fabric microstrip into a dynamic color rendering module with a fixed pixel density or a fixed size, and splicing a plurality of modules together to form a display device expandable to any size; and modulating, by a pixel selection chip, a voltage of the dynamic color rendering module through a gate voltage control drive circuit to display a simulated environment fusion pattern on the dynamic color rendering module.

2-7. (canceled)

8. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 1, wherein in the step 2, a volume ratio of the electronic ink microencapsule slurry to the adhesive is (1.52.5):1, the adhesive being a waterborne polyurethane, a waterborne polyacrylic acid, or a mixture of the waterborne polyurethane and the waterborne polyacrylic acid, a concentration of the adhesive being 10 wt %30 wt %, and a concentration of the electronic ink microencapsule slurry being 1.1 g/cm.sup.31.3 g/cm.sup.3.

9. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 8, wherein in the step 3, a concentration of silver nanowires in the silver nanowire slurry is 110.sup.2 wt %110.sup.3 wt %, and a concentration of single-walled carbon nanotubes in the single-walled carbon nanotube aqueous solution is 110.sup.3 wt %110.sup.4 wt %.

10. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 8, wherein in the step 5, a transparent polymer in the transparent polymer layer includes the waterborne polyurethane, the waterborne polyacrylic acid, or the mixture of the waterborne polyurethane and the waterborne polyacrylic acid, a concentration of the transparent polymer is 10 wt %30 wt %, and a thickness of the transparent polymer after curing is 1 m3 m.

11. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 1, wherein the conductive fabric microstrip is a double-layer structure formed by the conductive yarn and the insulating yarn through weaving, bonding, or knitting, the conductive region is located at a central surface of the conductive fabric microstrip, and the insulating region is located at an edge and a bottom of the conductive fabric microstrip.

12. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 11, wherein the conductive yarn includes at least one of silver-plated conductive yarn or conductive nano-material-coated conductive yarn, a yarn size of the at least one of silver-plated conductive yarn or conductive nano-material-coated conductive yarn being smaller than or equal to 100 D, and a monofilament size of the at least one of silver-plated conductive yarn or conductive nano-material-coated conductive yarn being smaller than or equal to 30 D; and the insulating yarn includes at least one of nylon, polyester, or polypropylene, or blended yarn, a yarn size of the at least one of nylon, polyester, or polypropylene, or blended yarn being smaller than or equal to 100 D, and a monofilament size of the at least one of nylon, polyester, or polypropylene, or blended yarn being smaller than or equal to 15 D.

13. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 1, wherein the silver nanowire slurry is an ethanol solution of the silver nanowires or an aqueous solution of the silver nanowires, and the silver nanowires have an average diameter of 15 nm20 nm and an aspect ratio of 10002000.

14. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 1, wherein the electronic ink microencapsule slurry includes electrophoretic particles that achieve two-color interchanging under different voltages or multicolor electrophoretic particles with different electrophoretic mobility, the two-color interchanging includes interchanging of at least one of black and white, blue and white, red and white, or green and white.

15. The method for preparing the electronic-ink-based colorful patterned color-changing fabric of claim 1, wherein the conductive fabric microstrip is further provided with the drive circuit for applying the voltage and the pixel selection chip for controlling the drive circuit to form a pattern on a surface of the color-changing fabric, the pixel selection chip being signally connected to the drive circuit, and a signal output end of the drive circuit being connected to the conductive region and the flexible transparent conductive layer respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a schematic diagram illustrating a structure of the colorful patterned color-changing fabric according to the present disclosure;

[0031] FIG. 2 is a schematic diagram illustrating a bilayer structure of a conductive fabric microstrip according to the present disclosure;

[0032] FIG. 3 is scanning electron microscope images of flexible transparent conductive layer of Embodiment 1, Embodiment 4, and Embodiment 5 of the present disclosure; and

[0033] FIG. 4 is a schematic diagram illustrating an exemplary relationship between reflectivity and bending times after the microstrip coated with a flexible transparent conductive layer in Embodiment 1 is flipped.

DETAILED DESCRIPTION

[0034] The technical solution of the present disclosure is described in further detail below in connection with the accompanying drawings and embodiments.

Embodiment 1

[0035] (1) Conductive yarn and insulating yarn were woven into a double-layer conductive fabric microstrip with a width of 12 mm using a double-layer warp knitting process. An edge of the double-layer conductive fabric microstrip was made of the insulating yarn. A center surface of the double-layer conductive fabric microstrip was made of the conductive yarn. The conductive yarn was 70D24F silver-plated conductive yarn. The insulating yarn was 70D24F nylon yarn. The conductive yarn was woven into a center region of the microstrip. A width of the conductive region was about 10 mm, and a width of the edge layer on both sides of the double-layer conductive fabric microstrip was about 1 mm. A square resistance of the conductive fabric microstrip was 1.

[0036] (2) The woven microstrip was coiled and introduced into a glue scrapper. A plurality of microstrips were arranged in parallel. Each of the microstrips was provided with a glue-dropping head. The electronic ink microencapsule slurry and a waterborne polyurethane mixed slurry were drop-applied to a center of the microstrip conductive region. The electronic ink microencapsule slurry had a density of 1.20 g/cm.sup.3. The polyurethane slurry was 9006A waterborne polyurethane produced by Shanghai Bihe Industrial and Trade Company. The electronic ink microencapsule slurry was mixed with polyurethane at a volume ratio of 2:1 through ultrasonic oscillation for 10 min. After the coating was completed, the microstrips were continuously dried and cured in a drying oven at 90 C. for 15 min. An overall thickness of a microstrip substrate and the cured electronic ink was about 200 m, and a thickness of the electronic ink microencapsule layer was 90 m.

[0037] (3) The cured continuous microstrips were introduced into a glue-coating machine. The plurality of microstrips were arranged in parallel. Each of the microstrips was provided with a glue-coating head. A diluted silver nanowire ethanol solution was uniformly brushed on a surface of the microstrip electronic ink cured adhesive layer through a narrow slit of the glue-coating head. The microstrips were continuously dried in the drying oven at 90 C. for 2 min. A square resistance of the dried and transparent silver nanowire layer was 150. A diluted single-walled carbon nanotube aqueous solution was spray-coated on the surface of the microstrips at a spray rate of 0.1 mL/s. The carbon nanotube was repeatedly spray-coated after hot air blow-drying. A hot air temperature was lower than 90 C. A total number of spray-coating was 2 times. After the hot air blow-drying, the conductive yarn was sewed with insulating filament in a direction perpendicular to a length of the microstrip, so that the conductive yarn conducted with the conductive layer of a conductive layer on the surface and was fixed with a bottom layer of the microstrips. An average diameter of the silver nanowires was 20 nm, and an aspect ratio of the silver nanowires was 1000. A concentration of silver nanowires in the silver nanowire slurry was 110.sup.2 wt %, and a concentration of single-walled carbon nanotubes in the single-walled carbon nanotube aqueous solution was 110.sup.3 wt %.

[0038] (4) The microstrips were introduced into a scraper, and a transparent polymer waterborne polyurethane 9006A slurry was uniformly coated on the surface of the microstrips. After coating, the microstrips were continuously dried and cured in a drying oven at 90 C. for 15 min, and an insulating encapsulation layer was formed after curing. After being wound up, the microstrips was prepared into a semi-finished product of colorful electronic ink microstrips. A concentration of the transparent polymer was 20 wt %, and a thickness after curing was 2 m.

[0039] The structure of the obtained colorful patterned color-changing fabric, referring to FIG. 1 and FIG. 2, may include a conductive fabric microstrip formed by weaving conductive yarn 2 and insulating yarn 1. The conductive yarn 2 may form a conductive region. The insulating yarn 1 may form an insulating region. An electronic ink microencapsule layer 3 may be arranged on the conductive region for image display. A flexible transparent conductive layer 4 may be arranged on the electronic ink microencapsule layer 3 for providing an electrophoretic color rendering voltage. A transparent polymer layer 5 may be arranged on the conductive fabric microstrip for encapsulation.

[0040] Before encapsulation, the conductive region was cut and disconnected by a low-energy Yttrium Aluminum Garnet (YAG) laser with a laser wavelength of 1.06 m, a spot size of smaller than 0.1 m, and a scanning speed of 0.1 m/s1 m/s to form independent square display pixels. A designed color-rendering fabric or camouflage cloth of any size was woven using the colorful microstrip semi-finished product and a vertical weaving manner in an order of red, green, and blue. A pixel drive chip was sewn on a back insulating layer. A pin of the pixel drive chip was connected to the conductive yarn connected to an upper electrode on a monochrome color block on a surface of a woven product through sewing to control color and grayscale of a colorful pixel unit. The pixel control circuit was connected to an output port of an image control circuit with the conductive yarn to achieve dynamic display of an image on a textile. An electronic ink microencapsule may optionally include two particles of opposite charges and different colors, such as blue-white interconversion, black-white interconversion, red-white interconversion, green-white interconversion, etc. to form a monochromatic pixel space mixing. The electronic ink microencapsule may also include a single microencapsule containing multi-color electrophoretic particles, the color mixing in the capsule may be controlled by adjusting a voltage, and the microstrips arranged in parallel may be sewn into a dynamic pattern display textile with any size, to achieve a richer display effect.

Embodiment 2

[0041] (1) Conductive yarn and insulating yarn was woven into a double-layer conductive fabric microstrip with a width of 12 mm using a double-layer warp knitting process. An edge was made of the insulating yarn. A center surface was made of the conductive yarn. The conductive yarn was 70D24F silver-plated conductive yarn. The insulating yarn was polyester yarn 75D72F. The conductive yarn was woven into a center region of the microstrip. A width of the conductive region was about 10 mm, and a width of the edge layer on both sides was about 1 mm. The conductive region was silver-plated with a thickness of about 2 m after the microstrip was woven, and a square resistance of the conductive microstrip was 1.

[0042] (2) The woven continuous microstrip was coiled and introduced into a glue scrapper. A plurality of microstrips were arranged in parallel. Each of the microstrips was provided with a glue-dropping head. The electronic ink microencapsule slurry and a waterborne polyurethane mixed slurry were drop-applied to the center of the microstrip conductive region. The electronic ink microencapsule slurry had a density of 1.10 g/cm.sup.3. The polyurethane slurry was 9006A waterborne polyurethane produced by Shanghai Bihe Industrial Trade Company. The electronic ink microencapsule slurry was mixed with polyurethane at a volume ratio of 1.5:1 through ultrasonic oscillation for 10 min. After the coating was completed, the microstrips were continuously dried and cured in a drying oven at 90 C. for 15 min. An overall thickness of a microstrip substrate and the cured electronic ink was about 200 m, and a thickness of the electronic ink microencapsule layer was 90 m.

[0043] (3) The cured continuous microstrips were introduced into a glue-coating machine. The plurality of microstrips were arranged in parallel. Each of the microstrips was provided with a glue-coating head. A diluted silver nanowire aqueous solution was uniformly brushed on a surface of the microstrip electronic ink cured adhesive layer through a narrow slit of the glue-coating head. The microstrips were continuously dried in the drying oven at 90 C. for 20 min. A square resistance of the dried and transparent silver nanowire layer was 150. A diluted single-walled carbon nanotube aqueous solution was spray-coated on the surface of the microstrips at a spray rate of 0.1 mL/s. The carbon nanotube was repeatedly spray-coated after hot air blow-drying. A hot air temperature was lower than 90 C. A total number of spray-coating was 2 times. After the hot air blow-drying, the conductive yarn was be sewed with insulating filament in a direction perpendicular to a length of the microstrips, so that the conductive yarn conducted with a conductive layer on the surface and was fixed with a bottom layer of the microstrips. An average diameter of the silver nanowires was 15 nm, and an aspect ratio of the silver nanowires was 2000. A concentration of silver nanowires in the silver nanowire slurry was 110.sup.3 wt %, and a concentration of single-walled carbon nanotubes in the single-walled carbon nanotube aqueous solution was 110.sup.4 wt %.

[0044] (4) The microstrips were introduced into a scraper, and a transparent polymer waterborne polyacrylic acid slurry was uniformly coated on the surface of the microstrips. After coating, the microstrips were continuously dried and cured in the drying oven at 90 C. for 15 min, and an insulating encapsulation layer was formed after curing. After being wound up, the microstrips were prepared into a semi-finished product of colorful electronic ink microstrip. A concentration of the transparent polymer was 10 wt %, and a thickness of the transparent polymer after curing was 1 m.

[0045] Before encapsulation, the conductive region was cut and disconnected by a low-energy YAG laser with a laser wavelength of 1.06 m, a spot size of smaller than 0.1 m, and a scanning speed of 0.1 m/s1 m/s to form independent square display pixels. A designed color-rendering fabric or camouflage cloth of any size was woven using the colorful microstrip semi-finished product and a vertical weaving manner in an order of red, green, and blue. A pixel drive chip was sewn on a back insulating layer. A pin of the pixel drive chip was connected to the conductive yarn connected to an upper electrode on a monochrome color block on a surface of a woven product through sewing to control color and grayscale of a colorful pixel unit. The pixel control circuit was connected to an output port of an image control circuit with the conductive yarn to achieve dynamic display of an image on a textile.

Embodiment 3

[0046] (1) Conductive yarn and insulating yarn was woven into a double-layer conductive fabric microstrip with a width of 12 mm using a double-layer warp knitting process. An edge was made of the insulating yarn. A center surface was made of the conductive yarn. The conductive yarn coating was conductive nanomaterial-coated conductive yarn. The nanomaterial in the coating of the conductive yarn was carbon nanotubes and silver nanowires, and the specification was 75D3F. The insulating yarn was polypropylene yarn, and the specification was 75D36F. The conductive yarn was woven into a center region of the microstrip using a high-density knitting process. A width of the conductive region was about 10 mm, and a width of the edge layer on both sides was about 1 mm. A square resistance of the conductive microstrip was 1.

[0047] (2) The woven continuous microstrip was coiled and introduced into a glue scrapper. A plurality of microstrips were arranged in parallel. Each of the microstrips was provided with a glue-dropping head. A mixed slurry of the electronic ink microencapsule slurry and the waterborne polyacrylic acid was drop-applied to a center of the microstrip conductive region. The electronic ink microencapsule slurry had a density of 1.35 g/cm.sup.3. The electronic ink microencapsule slurry was mixed with the waterborne polyacrylic acid at a volume ratio of 2.5:1 through ultrasonic oscillation for 10 min. After the coating was completed, the microstrips were continuously dried and cured in a drying oven at 90 C. for 15 min. An overall thickness of a microstrip substrate and the cured electronic ink was about 200 m, and a thickness of the electronic ink microencapsule layer was 90 m.

[0048] (3) The cured continuous microstrips were introduced into a glue-coating machine. The plurality of microstrips were arranged in parallel. Each of the microstrips was provided with a glue-coating head. A diluted silver nanowire aqueous solution was uniformly brushed on a surface of the microstrip electronic ink cured adhesive layer through a narrow slit of the glue-coating head. The microstrips were continuously dried in the drying oven at 90 C. for 20 min. A square resistance of the dried and the transparent silver nanowire layer was 150. A diluted single-walled carbon nanotube was spray-coated on the surface of the microstrips at a spray rate of 0.1 mL/s. The carbon nanotube aqueous solution was repeatedly spray-coated after hot air blow-drying. A hot air temperature was lower than 90 C. A total number of spray-coating was 2 times. After the hot air blow-drying, the conductive yarn was sewed with insulating filament in a direction perpendicular to a length of the microstrips, so that the conductive yarn conducted with the conductive layer on the surface and was fixed with a bottom layer of the microstrips. An average diameter of the silver nanowires was 20 nm, and an aspect ratio of the silver nanowires was 1000. A concentration of silver nanowires in the silver nanowire slurry was 110.sup.2 wt %, and a concentration of single-walled carbon nanotubes in the single-walled carbon nanotube aqueous solution was 110.sup.3 wt %.

[0049] (4) The microstrips were introduced into a scrapper, and a transparent polymer waterborne polyurethane 9006A slurry was uniformly coated on the surface of the microstrips. After coating, the microstrips were continuously dried and cured in the drying oven at 90 C. for 15 min, and an insulating encapsulation layer was formed after curing. After being wound up, the microstrips were prepared into a semi-finished product of colorful electronic ink microstrips. A concentration of the transparent polymer was 30 wt %, and a thickness of the transparent polymer after curing was 3 m.

[0050] Before encapsulation, the conductive region was cut and disconnected by a low-energy YAG laser with a laser wavelength of 1.06 m, a spot size of smaller than 0.1 m, and a scanning speed of 0.1 m/s to 1 m/s to form independent square display pixels. A designed color-rendering fabric or camouflage cloth of any size was woven using the colorful patterned color-changing fabric microstrip semi-finished product and a vertical weaving manner in an order of red, green, and blue. A pixel drive chip was sewn on a back insulating layer. A pin of the pixel drive chip was connected to the conductive yarn connected to an upper electrode on a monochrome color block on a surface of a woven product through sewing to control color and grayscale of a colorful pixel unit. The pixel control circuit was connected to an output port of an image control circuit with the conductive yarn to achieve dynamic display of an image on a textile.

Embodiment 4

[0051] The specific preparation process is the same as the specific preparation process of Embodiment 1, and the difference is that in step (3), only a silver nanowire ethanol solution was coated on the surface of the electronic ink cured adhesive layer of the microstrip, the microstrips were dried in the drying oven at 90 C. for 2 min, a flexible transparent conductive layer may be obtained after drying, and a colorful patterned color-changing fabric was further prepared.

Embodiment 5

[0052] The specific preparation process is the same as the specific preparation process of Embodiment 1, and the difference is that in step (3), the carbon nanotubes were repeatedly spray-coated, a number of spray-coating was 4 times, and a flexible transparent conductive layer was obtained, and a colorful patterned color-changing fabric was further prepared.

[0053] The flexible transparent conductive layers prepared in Embodiment 1, Embodiment 4, and Embodiment 5 may be subjected to scanning electron microscopy testing. It can be seen from FIG. 3 that (a) is the test result of Embodiment 1, (b) is the test result of Embodiment 4, (c) is the test result of Embodiment 5, only the silver nanowires are coated, silver nanowires may be sparsely distributed on the surface conductive layer, and when an amount of coated carbon nanotubes is relatively small, the carbon nanotubes may fill gaps of the silver nanowire network to form a charge layer; when there is a moderate density (square resistance of 100) of silver nanowires and carbon nanotubes, a light transmittance of the flexible transparent conductive layer is higher than 90%, and a flipping voltage of the flexible transparent conductive layer is lower than that of Embodiment 4.

[0054] The results of capacitance testing of the flexible conductive layers of Embodiment 1, Embodiment 4, and Embodiment 5 are shown in Table 1.

TABLE-US-00001 TABLE 1 Silver Silver Silver nanowires + nanowires + nanowires + Silver carbon carbon carbon nanowires nanotubes 1 nanotubes 2 nanotubes 3 Opaque 440 475 1085 1391 Electrodes Transparent 38 400 968 1164 Electrodes

[0055] Table 1 shows capacitance values (pF) of different flexible conductive layers at a 100 kHz voltage relative to an indium tin oxide (ITO) electrode for measuring an electronic ink layer with the same thickness. Silver nanowires, silver nanowires+carbon nanotubes 1, silver nanowires+carbon nanotubes 2, and silver nanowires+carbon nanotubes 3 are electrodes of Embodiment 4, Embodiment 1, Embodiment 5, and a silver nanowire layer coated with 6 layers of carbon nanotubes, respectively.

[0056] The stability of the electrode of Embodiment 1 is characterized by measuring the reflectivity after the flip discoloration after repeated bending, and the results show that the carbon nanotubes significantly increase the bending stability. FIG. 4 is a test result of Embodiment 1. When the bending diameter is 6 mm, there is no significant change in the discoloration characteristics of 10,000 bending.