CN109235025B

CN109235025B - Conductive carbon material/silk composite material and preparation method and application thereof

Info

Publication number: CN109235025B
Application number: CN201811054670.6A
Authority: CN
Inventors: 凌盛杰; 叶超; 任婧
Original assignee: ShanghaiTech University
Current assignee: ShanghaiTech University
Priority date: 2018-09-11
Filing date: 2018-09-11
Publication date: 2021-08-24
Anticipated expiration: 2038-09-11
Also published as: CN109235025A

Abstract

The invention provides a conductive carbon material/silk composite material and a preparation method and application thereof. The conductive yarn can be prepared by adopting the composite material, and then the textile can be prepared. Experiments prove that the composite material reserves the original mechanical property of silk, has conductive performance, expands the application of the silk in the field of intelligent fibers, and has the advantages of hydrophobicity, solvent resistance, self-cleaning, heat absorption and excellent performance.

Description

Conductive carbon material/silk composite material and preparation method and application thereof

Technical Field

The invention relates to a conductive carbon material/silk composite material and a preparation method and application thereof.

Background

Smart textiles (also referred to as electronic textiles) may have embedded therein electronic components and electronics such as batteries and light fixtures intended for track and field, extreme sports and military applications. As smart wearable systems, electronic textiles need to not only meet the necessary requirements of apparel, such as comfort, light weight, thermal insulation, and high mechanical strength, but also to provide added value to the wearer. For example, most electronic textiles need to protect against extreme environmental hazards, such as rain, solvent corrosion, and radiation damage, as well as monitor and regulate body temperature, reduce wind resistance, and control muscle vibration.

The manufacture of fibrous materials possessing conductive capabilities typically requires the use of conductive and semiconductive materials. The traditional strategy is to mix the metal wire directly with the polymer-based textile fibers to form a conductive yarn that can be knitted or stitched. However, because metal wires are hard materials, they are not suitable for fiber-based applications because the wires need to undergo significant stretching and bending during use, and moreover the addition of metal wires also increases the weight of the garment and reduces the comfort of wear. Carbon fibers, such as carbon-based fibers composed of carbon nanotubes (cnts) and graphene, are another useful semiconductor material for building electronic textiles. However, their cost, manufacturability, flexibility and compliance retention still do not meet the practical application requirements of smart fabrics.

As an ancient textile fiber, silk has unique advantages in the aspect of intelligent textile application. For example, silk is tougher than metal and carbon based fibers, and even tougher than kevlar in mechanical properties. Other advantages, such as light weight, low cost, sustainability, durability and good biocompatibility, can also avoid the use limitations of metals and carbon fibers. However, despite these excellent characteristics, practical applications of silk are dominated by apparel and decorations. The underlying reason is that they are poorly conductive and cannot be used directly in the construction of electronic textiles. In order to obtain conductive silk fibers, researchers have conducted various wet and dry spinning techniques to add conductive components (e.g., graphene and carbon nanotubes) to silk. However, the content of conductive elements in these regenerated silk fibers is far from sufficient to reach the conductive percolation threshold, thus limiting these methods for the preparation of electronic textiles. Carbonization of commercial silk textiles is another approach to making conductive textiles, but this approach can result in the mechanical advantage of natural silk being destroyed after high temperature carbonization. Therefore, it remains a significant challenge to produce electrically conductive silk fibers with mechanical properties that match the requirements of textiles and garments.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a conductive carbon material/silk composite material, a preparation method and a use thereof, which are used for filling the blank of the prior art and providing a completely new composite material.

In order to achieve the above and other related objects, the present invention provides a conductive carbon material/silk composite material, which is formed by adhering a conductive carbon material to silk through a method of etching and dip-coating degummed silk.

The silk comprises sericin and fibroin, and degumming is to remove sericin, wax grease, pigment and the like coated on the outer layer of the silk. The degummed silk can be purchased by the prior art or prepared by the prior art, for example, degummed silk by using a degumming solvent. The common degumming solvent is a compound of soap, proteolytic enzyme and surfactant; the alkaline agent is sodium hydroxide, sodium carbonate, sodium silicate, etc.

The etching and dip-coating method is that silk is etched by using an etching solvent, and then the conductive carbon material is added for dip-coating or the etching solvent and the conductive carbon material are added into the silk at the same time.

Further, the mass ratio of the degummed silk to the conductive carbon material is 5.5: 1-10: 1.

Further, the silk is any one or more of mulberry silk and various wild silks; more preferably mulberry silk.

Further, the conductive carbon material is selected from any one or more of carbon nano tube, graphene, graphite and graphite alkyne; more preferably carbon nanotubes and graphene.

Further, the solvent used for etching is a solvent capable of dissolving the surface of silk only.

Further, the solvent adopted by the etching is selected from one or more of hexafluoroisopropanol, hexafluoroacetone hydrate and ionic liquid.

Further, the ionic liquid (or ionic liquid) refers to a liquid composed entirely of ions, such as KCI at high temperature, KOH in a liquid state, and in this case, they are ionic liquids. In the technical scheme, any one or more of 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium chloride can be selected.

In another aspect of the present invention, there is provided a method for preparing the above conductive carbon material/silk composite material, comprising at least the steps of:

(3) providing degummed silk;

(4) mixing degummed silk, etching solvent and conductive carbon material to form mixed solution, culturing at 25-60 deg.C for 2 hr-60 days, and drying.

Further, the specific method of the step (1) is as follows: and (3) placing the silk in sodium bicarbonate, heating for 50-70 min at the temperature of 99-100 ℃, and washing.

Degummed silk is, of course, also commercially available.

Further, the degummed silk in the step (2) is scattered and mixed.

Further, the weight ratio of the degummed silk to the conductive carbon material in the mixed solution is 10:3-10: 5.

Further, the solid-liquid mass ratio in the mixed solution is 1:5-1: 50.

More preferably, the culturing time in the step (2) is 2 to 7 days.

Further, the drying is natural airing or drying at 50-60 ℃ for 2-3 hours.

In another aspect of the invention, the use of the above conductive carbon material/silk composite material for the preparation of conductive yarns is provided.

In another aspect of the invention, the conductive yarn is prepared from at least the conductive carbon material/silk composite material.

Another aspect of the present invention provides a method for preparing a conductive yarn by twisting not more than 100 conductive carbon material/silk composite.

In a further aspect of the invention there is provided the use of an electrically conductive yarn as described above for the manufacture of a textile product.

In another aspect of the invention, a textile is provided, and the raw material for preparing the textile at least comprises the conductive yarn.

Further, the textile is a glove or a knee pad.

In another aspect of the invention, a preparation method of the textile is provided, and the preparation method comprises the step of preparing the conductive yarn by using a machine sewing method, a knitting method or a hand knitting method.

As described above, the conductive carbon material/silk composite material of the present invention has the following beneficial effects:

(1) the conductive silk has the advantages of intact appearance, wide source of silk as a main raw material, pure nature, no pollution and biodegradability.

(2) The original multilayer structure of the silk (namely the silk microfiber, the silk nano fibril and the silk molecular chain) is reserved, silk fiber construction units with different hierarchical structures are arranged in the same material, and the construction units at all levels are not simply stacked but are crosslinked by a beta-folding structure formed by silk protein molecular chains, so that the original mechanical property of the silk is reserved to the maximum extent, and the application of the silk in the field of intelligent fibers is expanded. The composite material did not undergo plastic deformation or a decrease in tensile strength after mechanical tensile cycling test (40 cycles at a set strain of 5%), and thus had excellent spinnability.

(3) The composite material is washable, and after the composite material is washed by a standard program of a household washing machine for 10 times, the electrical property retention rate is over 80 percent, and no obvious appearance change exists.

(4) The addition of the conductive carbon material coating enables the composite material to be hydrophobic, solvent-resistant, self-cleaning and heat-absorbing.

(5) The resistance of the conductive silk yarn has repeatable responsiveness in the temperature rising and falling process, and organic solutions with different concentrations (different evaporation rates) are dripped, so that the composite material shows different responsiveness, and if the volatilization speed of the organic solution is slower, the response time of the resistance is longer.

(6) Has stress responsiveness, and the resistance under tensile conditions becomes large. For example, the resistance-time variation curve can be used for monitoring human body movement, gesture variation and the like by sewing the resistance-time variation curve on clothes or gloves.

(7) Textiles made with composite materials can convey acquired physical and chemical information according to changes in electrical parameters. The composite material integrates the advantages of silk and conductive carbon materials, and has application prospects in wearable equipment, human body enhancement, medical care monitoring and human-computer interfaces.

Drawings

FIG. 1a shows an optical photograph of the composite material prepared in example 1.

FIG. 1b shows a scanning electron microscope image of the composite material prepared in example 1.

FIG. 2a shows a photograph of the composite prepared in example 1 after washing with water.

Figure 2b shows a scanning electron microscope image of the composite prepared in example 1 after washing with water.

Figure 2c shows the resistance test of the composite prepared in example 1 after washing.

FIG. 3a is the mechanical property test chart of original silk-reeling mulberry silk in example 1.

FIG. 3b is a graph showing the mechanical properties of the composite material prepared in example 1.

FIG. 4a is a graph showing the mechanical stretch-recovery cycle test of the composite prepared in example 1.

FIG. 4b is a graph showing the change in resistance of the mechanical tensile cycle test of the composite material prepared in example 1.

Fig. 5a is a display diagram showing the hydrophilicity and hydrophobicity of the composite material prepared in example 1 after the composite material is made into a fabric.

Fig. 5b is a photograph showing the composite prepared in example 1 after the embroidery-patterned fabric is dissolved in hexafluoroisopropanol, formic acid, toluene, and acetone solvents in the upper right corner region.

FIG. 6a is a graph showing the surface temperature of the composite patterned by the embroidery machine after 30 seconds of irradiation with a soft infrared lamp, as prepared in example 1.

Fig. 6b shows a thermography of the conductive silk fabric with different layers prepared in example 1 during the cooling process after heating.

Fig. 6c shows the resistance of the composite prepared in example 1 during the temperature increase and decrease process.

Figure 7a shows the electrical signals transmitted for different movements of the knee wrap made in example 1 when worn.

Fig. 7b shows the electrical signals transmitted for different movements when the glove prepared in example 1 is worn.

Fig. 8a shows an optical photograph of the composite material prepared in example 2.

Figure 8b shows a scanning electron microscope image of the composite material prepared in example 2.

Fig. 9 shows the conductivity test for the composite material prepared in example 2.

Figure 10 shows the mechanical tensile test for the composite prepared in example 2.

Figure 11a shows the mechanical stretch-recovery cycle test for the composite prepared in example 2.

Figure 11b shows the electrical resistance of the composite prepared in example 2 as a function of the mechanical stretch-recovery cycle test.

Fig. 12a shows an optical photograph of the composite prepared in example 3.

Figure 12b shows a scanning electron microscope image of the composite material prepared in example 3.

FIG. 13a is a photograph of the composite prepared in example 3 after washing with water.

FIG. 13b shows a scanning electron microscope image of the washed surface of the composite prepared in example 3.

Fig. 13c shows the conductivity test after water washing for the composite prepared in example 3.

Figure 14 shows the mechanical tensile test for the composite prepared in example 3.

Figure 15a shows the mechanical stretch-recovery cycle test for the composite prepared in example 3.

Figure 15b shows the electrical resistance of the composite prepared in example 3 as a function of the mechanical stretch-recovery cycle test.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be understood that the processing equipment or apparatus not specifically identified in the following examples is conventional in the art. Furthermore, it is to be understood that one or more method steps mentioned in the present invention does not exclude that other method steps may also be present before or after the combined steps or that other method steps may also be inserted between these explicitly mentioned steps, unless otherwise indicated; it is also to be understood that a combined connection between one or more devices/apparatus as referred to in the present application does not exclude that further devices/apparatus may be present before or after the combined device/apparatus or that further devices/apparatus may be interposed between two devices/apparatus explicitly referred to, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

Example 1

(1) Preparing degummed mulberry silk according to the existing method, and processing filature mulberry silk filament in 0.5 wt% NaHCO₃Degumming in water solution (bath ratio 1: 200g/mL) at 100 deg.C for 30min, and replacing NaHCO under the same conditions₃And (3) continuously degumming the aqueous solution for 30min, soaking and washing the degummed fiber by using hot water, washing the degummed fiber by using deionized water, and drying the degummed fiber to obtain the degummed silk fiber.

(2) Hexafluoroisopropanol coating containing multi-walled carbon nanotubes was prepared by mixing 3mL of isopropanol dispersed multi-walled carbon nanotube solution (containing about 300mg of multi-walled carbon nanotubes, manufactured by china nano era) with 17mL of hexafluoroisopropanol in a 25mL sealed glass bottle with sufficient stirring.

(3) Preparing conductive mulberry silk fibers and yarns: 1.1044g of degummed silk-reeling mulberry silk filament bundle (a single filament bundle consists of about 30 silk cocoon monofilaments, the diameter of the silk bundle is 87 mu m, the length of the silk bundle can reach 1000mm) is immersed into the multi-walled carbon nanotube/isopropanol/hexafluoroisopropanol solution prepared in the step (2), and then the solution is placed in a sealed container at 60 ℃ for culturing for 3 days to obtain the mulberry silk fiber coated with the multi-walled carbon nanotube. Residual solvent was removed thoroughly by drying overnight in a fume hood.

The total mass of the finally obtained composite material was weighed to 1.2200 g.

(4) Dozens of silk fibers precoated with the multi-wall carbon nano tubes are arranged in parallel, and then the two ends are combined by appropriate twisting step to obtain the conductive single-twist long mulberry silk. The structure of the conductive mulberry silk yarn was characterized by scanning electron microscopy (JSM-7800) and the mechanical properties were characterized by testing with a universal mechanical stretcher (Instron 5966). The response of the material resistance to strain, heat and solvent is characterized by digital multimeter (CEM-DT9989 and Keithley-DMM6500) testing. The temperature of the surface of the material was characterized by thermography infrared (Fluke-DIS45) testing. The intelligent fabric substrate is common elastic fabric (comprising polyurethane knee pad and glove) purchased from the market.

The optical and scanning electron microscope images (fig. 1a, 1b) of the conductive silk yarn prepared by the method show that the carbon nanotubes are uniformly and firmly adhered to the surface of the silk, and the conductive silk fiber has good appearance and no obvious defects.

The appearance photograph (figure 2a) and the surface scanning electron microscope image (figure 2b) of the prepared conductive silk fiber after being continuously stirred for 1 hour and ultrasonically cleaned for 30 minutes by a glass rod and the conductivity test (figure 2c) after being cleaned by water show that the conductive silk yarn prepared by the method has the performance of being resistant to water washing without shedding the carbon nano tube.

The mechanical properties of the conductive silk yarns obtained by the method are not obviously reduced (shown in figures 3a-b) through the test of a universal tensile tester, and the specific expression is that the fracture strain of the treated mulberry silk yarns is basically maintained and the fracture strength is slightly improved compared with the original silk reeling mulberry silk filaments.

Mechanical tensile cycling tests showed that conductive mulberry silk showed good shape recovery after the first cycle (fig. 4 a). At a set strain of about 5% (which is close to the breaking strain of most woven plain fabrics), no plastic deformation or decrease in tensile strength occurred after 40 cycles. During this process, the resistance varied synchronously with the yarn deformation and release cycles and remained stable for 40 cycles (fig. 4 b).

Fig. 5a is the hydrophobicity demonstration of the fabric made by conductive silk, benefits from the unsmooth micro-nano structure in conductive silk surface, and during water droplet and rivers can not soak conductive silk, water contact angle is greater than 150, is super-hydrophobic surface. By dropping various solvents such as hexafluoroisopropanol, formic acid, toluene, acetone onto the pattern made of conductive silk yarn (fig. 5b), it can be seen that the base fabric has been completely dissolved away, while the part consisting of conductive silk remains intact in shape. The addition of the carbon tube with chemical inertia shows that the solvent resistance of the composite material is obviously improved.

Fig. 6a is a surface temperature of the embroidered woven pattern fabric containing conductive silk after 30 seconds of irradiation by a soft infrared lamp. The result shows that the conductive silk yarn prepared by the method has good heat absorption performance, in addition, fig. 6b is a thermograph of the conductive silk fabric with different layers in the cooling process after heating, and the result shows that the heat insulation performance of the fabric can be further improved by increasing the thickness of the conductive silk yarn. More notably, the electrical resistance of the conductive silk yarn is repeatable during the ramping (fig. 6 c).

As shown in fig. 7, the intelligent fabric for detecting human body movement based on the conductive silk yarn shows that the conductive silk yarn prepared by the method can be made into various intelligent fabrics through subsequent simple textile processing paths, is used for detecting human body movement, and is expected to provide translation tools for ordinary people to understand hearing-impaired people.

Example 2

(2) A hydrated hexafluoroacetone coating containing graphene was prepared, and 0.5mL of a graphene printing ink (containing about 200mg of graphene; purchased from Sigma Aldrich, usa) was added to 4mL of a hydrated hexafluoroacetone solvent with sufficient stirring and sufficiently stirred to be uniform, thereby obtaining a hydrated hexafluoroacetone-dispersed graphene coating.

(3) Preparing conductive mulberry silk fiber: 0.3846g of degummed silk reeling mulberry silk filament bundle (a single filament bundle is composed of about 30 silk cocoon monofilaments, the diameter of the filament bundle is 87 mu m, the length of the filament bundle can reach 1000mm) is immersed in the graphene/hydrated hexafluoroacetone solution prepared in the step (2), and then the solution is placed in a sealed container at 60 ℃ for culturing for 1 day to obtain the graphene-coated mulberry silk conductive functional fiber. Finally, residual solvent was removed thoroughly by drying overnight in a fume hood.

The total mass of the finally obtained composite material was weighed to 0.4528 g.

As can be seen from the optical photo (figure 8a) and the scanning electron microscope image (figure 8b) of the surface of the prepared graphene/silk composite fiber, the final composite material has uniform appearance and is uniformly coated with graphene.

Multimeter tests (fig. 9) show that the conductive silk composite material can also be prepared by using graphene as a raw material.

Mechanical tests show that the mechanical properties of the conductive silk fibers obtained by the method are not obviously changed (figure 10), finally, yarns prepared by twisting dozens of fibers keep good recovery in a 40 mechanical stretching cycle test (figure 11a), and the resistance of the yarns is correspondingly changed along with the cycle stretching process (figure 11 b).

Example 3

(2) Hexafluoroisopropanol coating containing multi-walled carbon nanotubes was prepared by mixing 5mL of isopropanol dispersed multi-walled carbon nanotube solution (containing about 500mg of multi-walled carbon nanotubes, manufactured by china nano era) with 15mL of hexafluoroisopropanol in a 25mL sealed glass bottle with sufficient stirring.

(3) Preparing conductive mulberry silk fibers and yarns: 1.0324g of degummed silk-reeling mulberry silk filament bundle (a single filament bundle is composed of about 25 silk cocoon monofilaments, the diameter of the silk bundle is 82 mu m, the length of the silk bundle can reach 1000mm) is immersed into the multi-wall carbon nano tube/isopropanol/hexafluoroisopropanol solution prepared in the step (2), and then the solution is placed in a sealed container at the temperature of 30 ℃ for culture for 7 days to obtain the mulberry silk fiber coated with the multi-wall carbon nano tube. Residual solvent was removed thoroughly by drying overnight in a fume hood.

The total mass of the finally obtained composite material was weighed to 1.2068 g.

(4) Dozens of silk fibers precoated with the multi-wall carbon nano tubes are arranged in parallel, and then the two ends are combined by appropriate twisting step to obtain the conductive single-twist long mulberry silk.

Test method conditions were as in example 1. The optical and scanning electron microscope images (fig. 12a, 12b) of the conductive silk yarn prepared by the method show that the carbon nanotubes are uniformly and firmly adhered to the surface of the silk, and the conductive silk fiber is intact in appearance and has no defects.

The appearance photograph (13a) and the surface scanning electron microscope image (fig. 13b) of the prepared conductive silk fiber after being subjected to ultrasonic cleaning for 300W for 30 minutes and for 1 hour by a glass rod in water and the conductivity test (fig. 13c) after being subjected to water cleaning show that the conductive silk yarn prepared by the method has the performance of resisting water cleaning without dropping the carbon nano tube.

The mechanical properties of the conductive silk yarn obtained by the method are not reduced (figure 14) through the test of a universal tensile tester, and the specific expression is that the fracture strain of the processed mulberry silk yarn is basically maintained and the fracture strength is slightly improved compared with the original silk reeling mulberry silk yarn.

Mechanical tensile cycling tests showed that conductive mulberry silk showed good shape recovery after the first cycle (fig. 15 a). At a set strain of about 5% (which is close to the breaking strain of most woven plain fabrics), no plastic deformation or decrease in tensile strength occurred after 40 cycles. During this process, the resistance varied synchronously with the yarn deformation and release cycles and remained stable for 40 cycles (fig. 15 b).

The above examples are intended to illustrate the disclosed embodiments of the invention and are not to be construed as limiting the invention. In addition, various modifications of the methods and compositions set forth herein, as well as variations of the methods and compositions of the present invention, will be apparent to those skilled in the art without departing from the scope and spirit of the invention. While the invention has been specifically described in connection with various specific preferred embodiments thereof, it should be understood that the invention should not be unduly limited to such specific embodiments. Indeed, various modifications of the above-described embodiments which are obvious to those skilled in the art to which the invention pertains are intended to be covered by the scope of the present invention.

Claims

1. The conductive carbon material/silk composite material is characterized in that the composite material is formed by adhering the conductive carbon material to silk through a method of carrying out etching synchronous dip coating on degummed silk on the degummed silk, wherein a solvent used for etching is a solvent capable of dissolving the surface of the silk only and being completely volatilized and removed after the silk obtains a conductive function, and the solvent is selected from one or two of hexafluoroisopropanol and hydrated hexafluoroacetone; the conductive carbon material is selected from any one or more of carbon nano tube, graphene, graphite and graphite alkyne;

the preparation method of the conductive carbon material/silk composite material at least comprises the following steps:

(1) providing degummed silk;

(2) mixing degummed silk, etching solvent and conductive carbon material to form mixed solution, culturing at 25-60 deg.C for 2 hr-60 days, and drying.

2. The conductive carbon material/silk composite material of claim 1, wherein the mass ratio of the degummed silk to the conductive carbon material is 5.5:1 to 10: 1.

3. The conductive carbon material/silk composite of claim 1, wherein: in the preparation method of the conductive carbon material/silk composite material, the specific method in the step (1) is as follows: and (3) placing the silk in sodium bicarbonate, heating for 50-70 min at the temperature of 99-100 ℃, and washing.

4. The conductive carbon material/silk composite of claim 1, wherein: in the preparation method of the conductive carbon material/silk composite material, the step (2) further comprises at least one or more of the following technical characteristics:

mixing the degummed silk after being scattered;

the weight ratio of the degummed silk to the conductive carbon material in the mixed solution is 10:3-10: 5;

the solid/liquid mass ratio in the mixed solution is 1:5-1: 50;

the culture time is 2 hours to 60 days;

the drying is natural airing or 2-3 hours at 50-60 ℃.

5. Use of the conductive carbon material/silk composite of any of claims 1 to 2 for the preparation of conductive yarns.

6. An electrically conductive yarn, characterized in that the raw material for preparing the electrically conductive yarn at least comprises the electrically conductive carbon material/silk composite material of any claim 1-2.

7. The method of preparing a conductive yarn according to claim 6, obtained by twisting not more than 100 pieces of conductive carbon material/silk composite.

8. Use of the conductive yarn of claim 6 for the preparation of textiles.

9. A textile article, characterized in that it is prepared from at least the conductive yarn of claim 6.

10. The textile of claim 9, wherein the textile is a glove or knee wrap.

11. A method of manufacturing a textile product according to claim 9 or 10, wherein the method comprises using the conductive yarn of claim 6 to manufacture the textile product by machine sewing, knitting or hand knitting.