阅读说明：本技术 一种基于不同织物组织CNTs涂层传感织物的制备方法 (Preparation method of CNTs coating sensing fabric based on different fabric textures ) 是由 邹梨花 杨莉 孙妍妍 阮芳涛 徐珍珍 花月 刘英存 曹昊天 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种基于不同织物组织CNTs涂层传感织物的制备方法,包括碱液处理,碳纳米管分散及包覆物吸附,吸潮,导电封膜制备等步骤,本发明制备出导电性能较好的柔性织物传感器,避免了传统金属纤维织物厚重、舒适性差的缺点。碳纳米管可均匀密集地吸附于织物上,使织物表面导电网络密集,利用淀粉基吸水性树脂包覆于CNTs、CNTs接枝长碳纤维及棉纤维表面,吸潮后,含水淀粉基吸水性树脂作为导电介质,将CNTs、CNTs接枝长碳纤维及导电封膜进一步导通形成三维立体导电网络,显著降低涂层织物的整体电阻。导电封膜的硅橡胶基质交联后可隔绝织物内外层,可保持淀粉基吸水性树脂含水量的稳定,维持导电传感性能的稳定。(The invention discloses a preparation method of a CNTs coating sensing fabric based on different fabric textures, which comprises the steps of alkali liquor treatment, carbon nanotube dispersion and coating adsorption, moisture absorption, conductive sealing film preparation and the like. The carbon nano tubes can be uniformly and densely adsorbed on the fabric, so that the conductive network on the surface of the fabric is dense, the surfaces of the CNTs, the CNTs grafted long carbon fibers and the cotton fibers are coated with the starch-based water-absorbent resin, after moisture absorption, the water-containing starch-based water-absorbent resin is used as a conductive medium, the CNTs grafted long carbon fibers and the conductive sealing film are further conducted to form a three-dimensional conductive network, and the overall resistance of the coated fabric is remarkably reduced. The silicone rubber matrix of the conductive sealing film can isolate the inner layer and the outer layer of the fabric after being crosslinked, can keep the stability of the water content of the starch-based water-absorbent resin, and can maintain the stability of the conductive sensing performance.)

1. A preparation method of a CNTs coating sensing fabric based on different fabric textures is characterized by comprising the following steps:

(1) soaking cotton fabrics with different fabric textures in alkali liquor, performing water bath constant temperature treatment, washing to be neutral, and then drying; the cotton fabric is woven by blended yarns of CNTs grafted long carbon fibers and cotton fibers;

(2) preparing a carbon nano tube dispersion liquid: dissolving 0.2-1.0 g of anhydrous starch-based water-absorbent resin in 50 mLN-methyl pyrrolidone to obtain a coating solution, heating to 60 ℃, dispersing carbon nanotubes in the coating solution, adding a surfactant, wherein the final concentration ratio of the carbon nanotubes to the surfactant is 1: 1-3, and performing ultrasonic treatment to obtain a carbon nanotube dispersion solution;

(3) flatly paving the cotton fabric dried in the step (1) in a container containing the carbon nano tube dispersion liquid, then carrying out constant-temperature oscillation treatment on the cotton fabric for 5 hours, and taking out and drying the cotton fabric subjected to the oscillation impregnation treatment;

(4) after drying, under the conditions of constant temperature and constant humidity of 25 ℃ and 100% relative humidity, absorbing moisture for 1-10 hours until the water content is 1-5 wt%;

(5) and uniformly coating the upper surface layer and the lower surface layer of the cotton fabric after moisture absorption with CNTs-containing silicon rubber to form a conductive sealing film, thus obtaining the CNTs coating sensing fabric with different fabric textures.

2. The method for preparing the CNTs coating sensing fabric based on different fabric textures as the claim 1 is characterized in that: the preparation method of the CNTs grafted long carbon fiber comprises the following steps:

(A) placing the PAN-based carbon fiber in a CVD furnace, and calcining for 1h at 450 ℃ under the protection of nitrogen to remove a surface sizing agent;

(B) modifying the surface of the desized carbon fiber by using an electrochemical anodic oxidation method: the electrolyte solution used was 5 wt% NH₄H₂PO₄The wire feeding speed of the aqueous solution is 40cm/min, the current is 0.3-0.5A, and the corresponding electrochemical treatment strength is 70-150C/g respectively;

(C) washing the electrochemically modified carbon fiber sample with deionized water for 5min, drying at 120 deg.C for 10min, and introducing Co (NO) with final concentration of 0.05M₃)₂·6H₂Soaking in O ethanol solution for 3min, guiding out, drying in a drying device at 80 deg.C for 10min, and collecting carbon fiber with catalyst coating by a filament collecting machine;

(D) putting the carbon fiber sample attached with the catalyst coating into an FRD-400-CVD deposition furnace, introducing 10L/min high-purity nitrogen, raising the furnace temperature to 450 ℃ at 10 ℃/min, and closing N₂Introducing 10L/min hydrogen to reduce for 1h, heating the furnace temperature to 550 ℃ at the heating rate of 25 ℃/min, and introducing C₂H₂、H₂And N₂The mixed gas is subjected to vapor deposition for 10min at the introduction rate of C₂H₂/H₂/N₂＝6/6/12L/min；

(E) After the deposition is finished, C is closed₂H₂And H₂And cooling the furnace temperature to room temperature under the protection of high-purity nitrogen of 10L/min to obtain the CNTs grafted long carbon fiber, wherein the air pressure in the furnace is constant at 0.02MPa in the whole reaction process.

3. The method for preparing the CNTs coating sensing fabric based on different fabric textures as the claim 1 is characterized in that: the preparation method of the conductive sealing film comprises the following steps:

(a) weighing 300mg of carbon nanotube, adding the carbon nanotube into 30m of 1 toluene solvent, stirring for 5min on a magnetic stirrer, then ultrasonically dispersing for 30min in an ultrasonic cleaning machine, then adding 10g of component A of Dow Corning Sylgard184PDMS silicone elastomer, magnetically stirring for 5min, ultrasonically dispersing for 30min, then adding 1g of component B of silicone rubber curing agent according to the mass ratio of 10:1, magnetically stirring for 5min, ultrasonically dispersing for 30min, and standing for 10min to obtain the silicone rubber containing CNTs;

(b) uniformly coating the CNTs-containing silicon rubber on the upper surface layer and the lower surface layer of the cotton fabric after moisture absorption, horizontally placing the cotton fabric in a vacuum oven with the relative vacuum degree of 0.05Mpa and the temperature of 40 ℃, taking out the cotton fabric after 40min, horizontally placing the cotton fabric in a fume hood for 12h to thoroughly volatilize toluene, and finally horizontally placing the cotton fabric in a constant-temperature blast drying oven with the temperature of 35 ℃ to cure for 4h to obtain a smooth and flat conductive sealing film without bubbles on the surface of the cotton fabric.

4. The method for preparing the CNTs coating sensing fabric based on different fabric textures as claimed in claims 1-3, wherein the different fabric textures are plain needle, 1+1 rib and 2+2 rib respectively; the alkali liquor is NaOH solution, and the concentration of the NaOH solution is 10 g/L; the water bath constant temperature treatment temperature in the step (1) is 60-70 ℃; the drying temperature in the step (1) is 60-80 ℃.

5. The method for preparing the CNTs coating sensing fabric based on different fabric textures as claimed in claims 1-4, wherein the surfactant in the step (2) is sodium dodecyl benzene sulfonate; the final concentration of the carbon nano-tubes in the step (2) is 3-11 mg/mL, the final concentration of the surfactant is 3-22 mg/mL, the ultrasonic treatment time is 30-90 min, and the ultrasonic treatment temperature is 30-60 ℃.

6. The method for preparing the CNTs coating sensing fabric based on different fabric textures as claimed in claims 1-5, wherein the bath ratio of the cotton fabric soaked in the carbon nanotube dispersion liquid in the step (3) is 1: 30-1: 40.

7. The method for preparing the CNTs coating sensing fabric based on different fabric textures as claimed in claim 1, wherein the temperature of the oscillatory immersion in the step (3) is 30-60 ℃ and the time is 30 min.

8. The method for preparing the CNTs coating sensing fabric based on different fabric textures as claimed in claim 1, wherein the drying temperature in the step (3) is 60-80 ℃, and the drying time is 1.5-2 h.

9. The method for preparing the CNTs coating sensing fabric based on different fabric textures as claimed in claim 1, further comprising repeating step 3 and then performing step 4.

Technical Field

The invention belongs to the technical field of flexible fabric sensors, and particularly relates to a preparation method of a CNTs coating sensing fabric based on different fabric textures.

Background

The preparation process of the dipping coating of the fabric sensor is economical and convenient, and is easy for large-scale production. The Carbon Nanotubes (CNTs) have the characteristics of good conductivity, corrosion resistance, light weight and the like, and have excellent physical and chemical properties, so that the carbon nanotubes are an ideal coating. The knitted fabric has good elastic recovery performance, wrinkle resistance and air permeability, and is comfortable to wear. Therefore, the coated fabric product obtained by coating the CNTs dispersion liquid on the knitted fabric has the characteristics of soft hand feeling, excellent elasticity, excellent air permeability and excellent conductivity, and the production process is simple, so that a good way is provided for the preparation of the fabric sensor.

At present, conductive fabrics made of conductive fibers such as metal and metal oxide fibers, carbon fibers and the like, which are purely spun or blended, conductive fabrics made of metal coating fabrics and organic conductive coatings and the like mainly appear on the market, but the metal fibers have the problems of poor wear resistance, poor toughness and easy corrosion, and the metal coating fabrics have the problems of easy corrosion and easy shedding. In the aspect of conductive fiber fabric, chinese patent CN104819734A utilizes polyaniline composite conductive yarn and spandex monofilament to weave a fabric resistance sensor. The chinese patent CN108045032A utilizes the graphene conductive filament, the graphene conductive staple fiber, the common filament and the common staple fiber to prepare the conductive woven fabric and the conductive non-woven fabric, so as to combine into the conductive sensing fabric.

Metal fibers and inorganic fibers are used in the development of fabric sensors as a good conductive material, but they have the disadvantages of poor wear resistance, easy breakage under the action of tensile, shearing and the like, and adverse effects on the operating performance of a weaving machine due to the conductivity. A fabric sensor woven with metal fibers has poor wearing feeling due to poor fiber flexibility.

CNTs is a carbon sixty allotrope newly found in recent years, can reach the nanometer level, and has the characteristics of good electrical conductivity, thermal conductivity, mechanical property, light weight and the like. The fabric has the characteristics of soft hand feeling, good elasticity and good air permeability, and the method for coating and finishing the fabric by using the CNTs dispersion liquid prepared from the CNTs and the dispersing agent can endow the fabric with excellent conductivity and ensure the comfort of the fabric, thereby providing a good way for preparing the fabric sensor.

In the prior art of preparing a coating conductive sensing fabric by using CNTs and a fabric, the CNTs are mostly adsorbed by adopting direct fabric adsorption or adsorbed after being coated by polyaniline in situ, when the CNTs are directly adsorbed, the CNTs in the fabric are mostly lapped by Van der Waals force to form a conductive structure, the conductive structure is loose, the lapping contact area is small, and the resistance of the fabric with the conductive structure is generally high; when the polyaniline in-situ coating method is used for preparing the conductive coating fabric, the polyaniline is non-conductive or has weak conductivity, so that the overall resistance of the fabric is higher, the conductivity is unsatisfactory, and further improvement steps are needed.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at various problems and defects existing in the preparation process of the CNTs coating sensing fabric at present, the invention provides a preparation method of the CNTs coating sensing fabric based on different fabric textures.

In order to solve the technical problems, the invention provides the following technical scheme:

a preparation method of a CNTs coating sensing fabric based on different fabric textures comprises the following steps:

(1) soaking cotton fabrics with different fabric textures in alkali liquor, performing water bath constant temperature treatment, washing to be neutral, and then drying; the cotton fabric is woven by blended yarns of CNTs grafted long carbon fibers and cotton fibers;

(2) preparing a carbon nano tube dispersion liquid: dissolving 0.2-1.0 g of anhydrous starch-based water-absorbent resin in 50 mLN-methyl pyrrolidone to obtain a coating solution, heating to 60 ℃, dispersing carbon nanotubes in the coating solution, adding a surfactant, wherein the final concentration ratio of the carbon nanotubes to the surfactant is 1: 1-3, and performing ultrasonic treatment to obtain a carbon nanotube dispersion solution;

(3) flatly paving the cotton fabric dried in the step (1) in a container containing the carbon nano tube dispersion liquid, then carrying out constant-temperature oscillation treatment on the cotton fabric for 5 hours, and taking out and drying the cotton fabric subjected to the oscillation impregnation treatment;

(4) after drying, under the conditions of constant temperature and constant humidity of 25 ℃ and 100% relative humidity, absorbing moisture for 1-10 hours until the water content is 1-5 wt%;

(5) and uniformly coating the upper surface layer and the lower surface layer of the cotton fabric after moisture absorption with CNTs-containing silicon rubber to form a conductive sealing film, thus obtaining the CNTs coating sensing fabric with different fabric textures.

Preferably, the preparation method of the CNTs grafted long carbon fiber comprises the following steps:

(A) placing the PAN-based carbon fiber in a CVD furnace, and calcining for 1h at 450 ℃ under the protection of nitrogen to remove a surface sizing agent;

(B) modifying the surface of the desized carbon fiber by using an electrochemical anodic oxidation method: the electrolyte solution used was 5 wt% NH₄H₂PO₄Aqueous solution at a wire-moving speed of40cm/min, the current is 0.3-0.5A, and the corresponding electrochemical treatment intensity is 70-150C/g respectively;

(C) washing the electrochemically modified carbon fiber sample with deionized water for 5min, drying at 120 deg.C for 10min, and introducing Co (NO) with final concentration of 0.05M₃)₂·6H₂Soaking in O ethanol solution for 3min, guiding out, drying in a drying device at 80 deg.C for 10min, and collecting carbon fiber with catalyst coating by a filament collecting machine;

(D) putting the carbon fiber sample attached with the catalyst coating into an FRD-400-CVD deposition furnace, introducing 10L/min high-purity nitrogen, raising the furnace temperature to 450 ℃ at 10 ℃/min, and closing N₂Introducing 10L/min hydrogen to reduce for 1h, heating the furnace temperature to 550 ℃ at the heating rate of 25 ℃/min, and introducing C₂H₂、H₂And N₂The mixed gas is subjected to vapor deposition for 10min at the introduction rate of C₂H₂/H₂/N₂＝6/6/12L/min；

(E) After the deposition is finished, C is closed₂H₂And H₂And cooling the furnace temperature to room temperature under the protection of high-purity nitrogen of 10L/min to obtain the CNTs grafted long carbon fiber, wherein the air pressure in the furnace is constant at 0.02MPa in the whole reaction process.

Preferably, the preparation method of the conductive sealing film is as follows:

(a) weighing 300mg of carbon nanotube, adding the carbon nanotube into 30m of 1 toluene solvent, stirring for 5min on a magnetic stirrer, then ultrasonically dispersing for 30min in an ultrasonic cleaning machine, then adding 10g of component A of Dow Corning Sylgard184PDMS silicone elastomer, magnetically stirring for 5min, ultrasonically dispersing for 30min, then adding 1g of component B of silicone rubber curing agent according to the mass ratio of 10:1, magnetically stirring for 5min, ultrasonically dispersing for 30min, and standing for 10min to obtain the silicone rubber containing CNTs;

(b) uniformly coating the CNTs-containing silicon rubber on the upper surface layer and the lower surface layer of the cotton fabric after moisture absorption, horizontally placing the cotton fabric in a vacuum oven with the relative vacuum degree of 0.05Mpa and the temperature of 40 ℃, taking out the cotton fabric after 40min, horizontally placing the cotton fabric in a fume hood for 12h to thoroughly volatilize toluene, and finally horizontally placing the cotton fabric in a constant-temperature blast drying oven with the temperature of 35 ℃ to cure for 4h to obtain a smooth and flat conductive sealing film without bubbles on the surface of the cotton fabric.

Preferably, the different fabric weaves are plain knitting, 1+1 rib, 2+2 rib; the alkali liquor is NaOH solution, and the concentration of the NaOH solution is 10 g/L; the water bath constant temperature treatment temperature in the step (1) is 60-70 ℃; the drying temperature in the step (1) is 60-80 ℃.

Preferably, the surfactant in the step (2) is sodium dodecyl benzene sulfonate; the final concentration of the carbon nano-tubes in the step (2) is 3-11 mg/mL, the final concentration of the surfactant is 3-22 mg/mL, the ultrasonic treatment time is 30-90 min, and the ultrasonic treatment temperature is 30-60 ℃.

Preferably, the bath ratio of the cotton fabric soaked in the carbon nanotube dispersion liquid in the step (3) is 1: 30-1: 40.

Preferably, the temperature of the shaking impregnation in the step (3) is 30-60 ℃ and the time is 30 min.

Preferably, the drying temperature in the step (3) is 60-80 ℃, and the time is 1.5-2 h.

Preferably, the method further comprises the step 4 after the step 3 is circularly repeated.

The invention has the following beneficial effects:

1. the prepared flexible fabric sensor with better conductivity has the advantages of thin and light coating fabric, good conductivity effect, controllable thickness, adjustable structure, simple requirement on required experimental operation conditions, low energy consumption, no need of expensive equipment and low production cost, and can be industrially produced on the traditional sizing or printing and dyeing equipment. The carbon nanotube coated fabric also has the characteristics of softness and comfort, and the defects of heavy weight and poor comfort of the traditional metal fiber fabric are avoided.

2. The carbon nano tubes can be uniformly and densely adsorbed on the fabric by using a simple dipping-coating process, so that the conductive network on the surface of the fabric is dense, the surfaces of the CNTs, the CNTs grafted long carbon fibers and the cotton fibers are coated with the starch-based water-absorbent resin, after moisture absorption, the water-containing starch-based water-absorbent resin is used as a conductive medium, the CNTs grafted long carbon fibers and the conductive sealing film are further conducted to form a three-dimensional conductive network, and the overall resistance of the coated fabric is remarkably reduced.

3. The CNTs graft structure formed on the surface of the long carbon fiber through chemical deposition can reduce the resistance generated by natural lapping of the CNTs and the main carbon fiber, after the CNTs and the main carbon fiber are blended into yarn, the long carbon fiber can be used as a framework of a conductive network, the deposited CNTs and the adsorbed CNTs can be lapped to form a branch conductive structure, and the branch conductive structure can be communicated with other main carbon fiber to form a three-dimensional conductive network;

4. by increasing the times of adsorbing the coating, the conductivity of the fabric is continuously improved; the conductivity of the fabric is continuously improved by increasing the concentration of the carbon nano tubes in the dispersion liquid; in the three fabric tissues, the plain structure has the optimal conductivity, and the 2+2 rib coating knitted fabric has the optimal sensing performance.

5. The inner layer and the outer layer of the fabric can be isolated after the silicon rubber matrix of the conductive sealing film is crosslinked, the stability of the water content of the starch-based water-absorbent resin can be kept, excessive water absorption expansion or drying water loss is prevented, the water content of a conductive medium is kept stable, the stability of the conductive sensing performance is maintained, meanwhile, the whole thickness of the fabric is increased after the conductive sealing film is coated, the silicon rubber is not conductive, if CNTs are not added, the resistance of the fabric is increased inevitably, therefore, the conductive sealing film is prepared from liquid CNTs-containing silicon rubber, the CNTs contained in the conductive sealing film can be conducted with the CNTs adsorbed in the fabric, a three-dimensional conductive network is formed by combining the CNTs grafted long carbon fibers in the yarn.

Drawings

FIG. 1 is a scanning electron microscope picture of the cotton fabric finished in the step (4) when the concentration of the carbon nano tubes in the carbon nano tube dispersion liquid is 3mg/mL and the concentration of sodium dodecyl benzene sulfonate is 3 mg/mL;

FIG. 2 is a scanning electron microscope picture of the cotton fabric finished in the step (4) when the concentration of the carbon nano tubes in the carbon nano tube dispersion liquid is 6mg/mL and the concentration of sodium dodecyl benzene sulfonate is 18 mg/mL;

FIG. 3 is a scanning electron microscope picture of the cotton fabric finished in the step (4) when the concentration of the carbon nanotubes in the carbon nanotube dispersion liquid is 11mg/mL and the concentration of sodium dodecylbenzenesulfonate is 22 mg/mL;

FIG. 4 is a scanning electron microscope image of the carbon nanotube coated fabric finished in steps (3) + (4) in example 2;

FIG. 5 is a scanning electron microscope image of the carbon nanotube coated fabric finished in step (3). times.3 + (4) in example 2;

FIG. 6 is a scanning electron microscope image of the carbon nanotube coated fabric finished in step (3). times.5 + (4) in example 2;

FIG. 7 is a strain sensing curve of a plain cotton fabric finished in the steps (3) + (4) in example 1;

FIG. 8 is a strain sensing curve of 1+1 rib cotton fabric finished in the steps (3) + (4) in example 1;

FIG. 9 is a strain sensing curve of 2+2 rib cotton fabric finished in the steps (3) + (4) in example 1;

Detailed Description

The following examples are included to provide further detailed description of the present invention and to provide those skilled in the art with a more complete, concise, and exact understanding of the principles and spirit of the invention.