Highly elastic hydrogel fiber with conductivity insensitive to stretching and preparation method and application thereof

Abstract

The present invention belongs to the technical field of functional hydrogel fiber preparation, and specifically discloses a high-elastic hydrogel fiber with insensitive conductivity to stretching, and a preparation method and application thereof, wherein the hydrogel fiber comprises an outer shell and an inner core; the outer shell is composed of a polymer, and the inner core comprises PEDOT:PSS, glutaraldehyde and polyvinyl alcohol; the outer shell and the inner core are coaxial. The hydrogel fiber has both high conductivity and high elasticity, and the conductivity hardly changes under large tensile deformation conditions, and has great application potential in the field of preparing intelligent wearable textiles that are resistant to motion interference.

Description

Technical Field

[0001] The invention belongs to the technical field of functional hydrogel fiber preparation, and specifically relates to a high-elastic hydrogel fiber with conductivity insensitive to stretching, and a preparation method and application thereof. Background Art

[0002] Most smart wearable fabrics use metal wires to connect external power sources and electronic display systems to achieve charge and signal transmission. Compared with metal wires, polymer conductive fibers have the advantages of light weight, softness, breathability, comfort, and easy weaving, and have broad application prospects in the field of smart wearables. Ideal polymer conductive fibers must not only have excellent conductivity, but also have high softness and elasticity to meet the high fit of the fabric to the human body curve when worn. Polymer conductive hydrogel fibers have excellent biocompatibility and mechanical properties similar to those of biological tissues, and are ideal carriers for the preparation of flexible electronic devices. At present, research on polymer conductive fibers has made significant progress, but there is still huge research space in many aspects, including: further optimization of properties such as conductivity, tensile resilience, and water washability; overcoming the significant effect of stretching on conductivity; and achieving continuous production of high-performance conductive fibers.

[0003] Microfluidics is a technology that precisely manipulates the flow of microscale liquids in microchannels. It can controllably construct hydrogel microbeads and microfibers with diverse morphologies, structures, compositions, and functions, and is widely used in the fields of biological sciences, medical sciences, etc. Due to its excellent precision and flexibility, microfluidics can be used to prepare fibers with complex internal components and structures, thus filling the gap in traditional fiber preparation methods (electrospinning, melt spinning, and wet spinning), and providing an excellent platform for the innovative design and controllable preparation of new functional fiber materials. Chinese patent application CN114854677A discloses a microfluidic bionic fiber for cell culture meat production and its preparation method and application. The microfluidic bionic fiber has a "shell-core" structure, the shell is formed by cross-linking a polymer with cell non-adhesiveness, and the core wrapped by the shell is a hydrogel solution mixed with seed cells. The invention constructs bionic fibers based on microfluidic technology, and the preparation method is simple, the molding is fast, and the reaction is mild. The prepared bionic fibers can be used for cell culture meat production after cultivation. The seed cells in the bionic fibers are oriented, migrated, and fused in the fiber carrier, thereby significantly improving the differentiation ability of the seed cells, increasing the synthesis of muscle-related proteins, and improving the production efficiency of cell culture meat. However, the above-mentioned microfluidic bionic fibers do not belong to conductive fibers and are not suitable for the field of flexible electronic devices. At present, there is still a lack of relevant research on the microfluidic molding of conductive fibers, and the conductive fibers developed and prepared also have problems such as unsatisfactory conductivity and large changes in conductivity under tensile deformation conditions.

[0004] Therefore, there is an urgent need to find a composite hydrogel fiber that has high conductivity, high elasticity and conductivity stretching insensitivity. Summary of the invention

[0005] As used herein, the singular forms "a," "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise. Numerical ranges recited by endpoints include all numbers and fractions within the corresponding ranges, as well as the recited endpoints.

[0006] In view of the problems existing in the prior art, the present invention provides a highly elastic hydrogel fiber with electrical conductivity that is insensitive to stretching, and a preparation method and application thereof. The hydrogel fiber has both high electrical conductivity and high elasticity, and its electrical conductivity hardly changes under large tensile deformation conditions. It shows great application potential in the field of preparing smart wearable textiles that are resistant to motion interference.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] The invention provides a high-elastic hydrogel fiber with conductivity insensitive to stretching, comprising an outer shell and an inner core; the outer shell is composed of a polymer, and the inner core comprises PEDOT:PSS, glutaraldehyde and polyvinyl alcohol; the outer shell and the inner core are coaxial.

[0009] Preferably, the outer diameter of the high-elastic hydrogel fiber is 0.5-2.0 mm.

[0010] Preferably, the component of the inner core is a mixed liquid of PEDOT:PSS, glutaraldehyde and polyvinyl alcohol.

[0011] Preferably, the amount of PEDOT:PSS added to the blended liquid is 0.5wt%-2.0wt%; the amount of polyvinyl alcohol added is 1wt%-3wt%; and the amount of glutaraldehyde added is 1.0 μL / mL-4.0 μL / mL.

[0012] Further preferably, the amount of PEDOT:PSS added to the blended liquid is 0.83 wt %; the amount of polyvinyl alcohol added is 2.5 wt %; and the amount of glutaraldehyde added is 2.5 μL / mL.

[0013] Preferably, the polymer includes at least one of polyurethane and silicone rubber.

[0014] More preferably, the polymer is polyurethane.

[0015] Preferably, the concentration of the polymer is 160 mg / mL-240 mg / mL.

[0016] The present invention also provides a method for preparing the above-mentioned high-elastic hydrogel fiber, comprising the following steps:

[0017] S1. preparing microfluidic inner layer fluid: preparing a mixed solution of PEDOT:PSS, glutaraldehyde and polyvinyl alcohol as the microfluidic inner layer fluid;

[0018] S2. Preparation of microfluidic middle layer fluid: Preparation of DMSO solution of polymer as microfluidic middle layer fluid;

[0019] S3, preparing microfluidic outer layer fluid: preparing DMSO / H2O mixed solution as microfluidic outer layer fluid;

[0020] S4. Preparation of highly elastic hydrogel fibers: respectively introducing the prepared microfluidic inner layer fluid, microfluidic middle layer fluid and microfluidic outer layer fluid into the inner, middle and outer phase channels of the microfluidic device to form a stable laminar flow structure in the outlet capillary to obtain the highly elastic hydrogel fibers.

[0021] Preferably, the flow rate of the inner layer fluid in step S1 is 0.6-1.4 mL / h; the flow rate of the middle layer fluid in step S2 is 3-5 mL / h; and the flow rate of the outer layer fluid in step S3 is 30-50 mL / h.

[0022] Further preferably, the flow rate of the inner layer fluid in step S1 is 1.0 mL / h; the flow rate of the middle layer fluid in step S2 is 4 mL / h; and the flow rate of the outer layer fluid in step S3 is 40 mL / h.

[0023] Preferably, the channel structure of the microfluidic device in step S4 is in the form of an inner phase channel and an outer phase channel coaxially nested.

[0024] The present invention also provides an application of the above-mentioned high-elastic hydrogel fiber or the high-elastic hydrogel fiber prepared by the above-mentioned preparation method in the preparation of intelligent wearable textiles that are resistant to motion interference.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The high-elastic hydrogel fiber of the present invention has both high electrical conductivity and high elasticity. The electrical conductivity hardly changes under large tensile deformation conditions, and it shows great application potential in the field of preparing smart wearable textiles that are resistant to motion interference. The present invention prepares continuous, large-scale, structurally uniform and size-controllable high-elastic hydrogel fibers based on microfluidic technology. The equipment involved is low-cost, the preparation conditions are mild, the operation is simple, and the molding is rapid. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The conductivity of the high elastic hydrogel fiber obtained with different inner core fluids;

[0028] Figure 2 The relative resistance of the highly elastic hydrogel fiber obtained with different inner core fluids varies with strain;

[0029] Figure 3 : is a stress-strain curve diagram of the high elastic hydrogel fiber obtained in Example 2, wherein a is a stress-strain curve diagram, and b is a tensile recovery stress-strain curve diagram;

[0030] Figure 4 This is a graph showing the change in relative resistance of the highly elastic hydrogel fiber obtained in Example 2 as a function of tensile strain;

[0031] Figure 5 This is a graph showing the change in relative resistance of the high-elastic hydrogel fiber obtained in Example 2 as a function of the bending angle;

[0032] Figure 6 Graph showing the effect of changes in flow rate ratio on the inner diameter and shell thickness of the high-elastic hydrogel fiber obtained in Example 2, wherein a is the inner diameter effect graph, and b is the shell thickness effect graph;

[0033] Figure 7 This is a diagram of the application of the highly elastic hydrogel fiber obtained in Example 2 in conductive fibers. DETAILED DESCRIPTION

[0034] The present invention is described below through specific embodiments to make the technical solution of the present invention easier to understand and grasp, but the present invention is not limited thereto, and the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0035] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0036] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. The experimental methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0037] It should be noted that

[0038] PEDOT:PSS is poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid; GA is glutaraldehyde; PVA is polyvinyl alcohol; PU is polyurethane.

[0039] Example 1 Preparation of microfluidic fluid

[0040] 1. Preparation of inner layer fluid: 1 g of 15 wt% PVA aqueous solution and 5 mL of 10 mg / mL PEDOT:PSS solution were fully stirred and mixed. During the stirring process, 15 μL of GA cross-linking agent was added and the stirring was continued until the mixture was uniform to obtain a mixed solution with a PVA mass fraction of 2.5 wt%, a PEDOT:PSS mass fraction of 0.83 wt%, and a GA volume fraction of 2.5 μL / mL as the inner layer fluid.

[0041] 2. Preparation of middle-layer fluid: Add 0.8 g of PU pellets into 5 mL of DMSO solvent, heat and stir until completely dissolved to obtain a PU / DMSO solution with a PU concentration of 160 mg / mL, which is used as the middle-layer fluid.

[0042] 3. Preparation of outer fluid: Thoroughly mix 30 mL DMSO and 70 mL H2O to obtain a DMSO / H2O solution as the outer coagulation bath fluid.

[0043] Example 2 Preparation of High Elastic Hydrogel Fiber

[0044] 1. Microfluidic fiber forming device: including a capillary with an outer diameter of 3mm and an inner diameter of 2mm for the outer layer; a capillary with an outer diameter of 1.5mm and an inner diameter of 1.12mm for the middle layer; and a capillary with an outer diameter of 1mm and an inner diameter of 0.3mm for the inner layer. Using an 18G dispensing needle, the inner and outer capillaries are sleeved to obtain the needle required for microfluidic fiber forming. The obtained microfluidic needle has three fluid inlets and one outlet. A syringe pump is used as a fluid push device, and a polytetrafluoroethylene tube is used to connect the syringe pump to the needle.

[0045] 2. The prepared inner layer fluid PEDOT:PSS / PVA / GA blended liquid flows out from the inner layer microfluidic channel, the middle layer fluid PU / DMSO solution flows out from the middle layer microfluidic channel, and the outer layer fluid DMSO / H2O mixed solution flows out from the outer layer microfluidic channel. Different pumping amounts are injected into the microfluidic needle from the corresponding fluid inlets through a syringe pump to form a stable laminar flow in the outlet capillary to obtain the highly elastic hydrogel fiber.

[0046] Among them, by adjusting the inner layer fluid components, the mass fractions of PEDOT:PSS and PVA were set to 0.83wt% and 2.5wt%, respectively, the GA volume was set to 2.5μL / mL, and the middle fluid components were adjusted to set the PU concentration to 160mg / mL. In addition, the flow rates of the outer, middle, and inner layer fluids in the microfluidic molding needle were controlled to V 外 =40mL / h; V 中 =4.0mL / h; V内 =1.0 mL / h, and microfluidic spinning was performed.

[0047] Effect Example 1 Performance Test of Hydrogel Fiber

[0048] 1. Effect of different contents of internal fluid on the conductivity of hydrogel fibers

[0049] According to the internal fluid formula shown in Table 1 and the preparation method of Example 1 and Example 2, high-elastic hydrogel fibers were prepared, and the conductivity of each high-elastic hydrogel fiber was detected by an electrochemical workstation.

[0050] Table 1 Internal fluid formulation

[0051]

[0052] The results are as follows Figure 1 , Figure 2 And as shown in Table 2.

[0053] When the components PEDOT:PSS in the internal fluid of the present invention are 0.5wt%-2.0wt%, polyvinyl alcohol is 1wt%-3wt% and glutaraldehyde is 1.0μL / mL-4.0μL / mL, when the PEDOT:PSS content is fixed, the conductivity of the obtained fiber decreases with the increase of PVA concentration; when the PVA content is fixed, the conductivity of the obtained fiber increases with the increase of PEDOT:PSS concentration, and the relative resistance changes more significantly with the increase of strain.

[0054] Table 2 Relationship between different internal fluid formulations and conductivity

[0055]

[0056] 2. Stress-strain curve determination of high elastic hydrogel fibers

[0057] Experimental method: Select the high elastic hydrogel fiber of Example 2, fix the hydrogel fiber with an initial length of 40 mm between the upper and lower clamps of the tensile machine, perform a tensile strength test at a tensile speed of 40 mm / min, and record the tensile strength and elongation at break when the fiber is broken. Take the average value of 5 test results. When performing the cyclic tensile test, the stretching and retraction speeds are both 40 mm / min.

[0058] The experimental results are as follows Figure 3 As shown, Figure 3 a indicates that the high elastic hydrogel fiber has good tensile deformation performance, and its tensile strain can reach 365%; in addition, Figure 3 b indicates that the high-elastic hydrogel fiber has good elasticity, and the cyclic tensile test results show that after undergoing 100% tensile deformation, the permanent deformation of the fiber is about 17%.

[0059] 3. Resistance detection of high elastic hydrogel fiber

[0060] Experimental method: According to the internal fluid formula shown in Table 1, each high-elastic hydrogel fiber was prepared according to the preparation method of Example 1 and Example 2. Bare copper wires with a diameter of 0.05 mm were connected to the conductive inner core from both ends of the high-elastic hydrogel fiber and fixed with photocurable epoxy resin. The copper wires at both ends were connected to the positive and negative electrodes of the electrochemical workstation respectively, the output voltage was set to 1V, the current I passing through the high-elastic hydrogel fiber was recorded and the resistance was calculated. The high-elastic hydrogel fiber was stretched to different strains and its resistance change was tested.

[0061] The experimental results are as follows Figure 4 As shown in Table 3: When the tensile strain of the highly elastic hydrogel fibers prepared by Samples 1-3 reaches 100%, the relative resistance change does not exceed 0.5.

[0062] Table 3 Relative resistance changes of high elastic hydrogel fibers with different inner core fluid formulas under 100% strain

[0063]

[0064] 4. Detection of the change of relative resistance of high elastic hydrogel fiber with bending degree

[0065] Experimental method: According to the internal fluid formula shown in Table 1, each highly elastic hydrogel fiber was prepared according to the preparation method of Example 1 and Example 2. Bare copper wires with a diameter of 0.05 mm were connected to the conductive inner core from both ends of the highly elastic hydrogel fiber and fixed with photocurable epoxy resin. The copper wires at both ends were connected to the positive and negative electrodes of the electrochemical workstation respectively, the output voltage was set to 1V, the current I passing through the highly elastic hydrogel fiber was recorded and the resistance was calculated. The highly elastic hydrogel fiber was bent to different angles to test its resistance change. The specific results are shown in Tables 4 and Figure 5 .

[0066] Table 4 Relative resistance changes of high elastic hydrogel fibers with different inner core fluid formulas under 180° bending

[0067]

[0068] When the bending angle of the highly elastic hydrogel fiber prepared by Sample 1-3 reaches 180°, the relative resistance change does not exceed 0.7.

[0069] 4. Detection of the influence of inner core diameter and outer diameter of high elastic hydrogel fiber on the flow rate of outer, middle and inner layer fluid

[0070] The effect of the inner and middle layer fluid flow rates during the microfluidic molding process on the size of the highly elastic hydrogel fibers in Example 2 was investigated.

[0071] Experimental method: The outer fluid flow rate (Q out ) is fixed at 40 mL / h, and the inner fluid flow rate (Q in ) and the flow rate of the intermediate layer fluid (Q mid ), the microfluidic molding of the high-elastic hydrogel fiber is completed. The inner and outer diameters of the obtained high-elastic hydrogel fiber are measured, and the shell thickness is calculated.

[0072] The experimental results are as follows Figure 6 As shown: While maintaining the outer fluid flow rate (Q out ) and the flow rate of the intermediate layer fluid (Q mid ) remains unchanged, the inner fluid velocity (Q in ) increases from 0.6mL / h to 1.4mL / h, the inner diameter of the molded fiber (D inner ) gradually increases while the fiber shell thickness gradually decreases. out and Q in If Q mid When the flow rate increases from 3 mL / h to 5 mL / h, the inner diameter of the formed fiber decreases while the thickness of the fiber shell gradually increases.

[0073] In summary, the high-elastic hydrogel fibers prepared from samples 1-3 have high conductivity and high elasticity, and their relative resistance hardly changes under large tensile deformation conditions. Although the relative resistance of the high-elastic hydrogel fibers prepared from sample 4 does not change much under large tensile deformation conditions, the conductivity does not meet the requirements; the high-elastic hydrogel fibers prepared from sample 5 have high conductivity, but low elasticity, and their relative resistance changes too much under large tensile deformation conditions, and cannot resist motion interference well, and are not suitable for preparing smart wearable devices that resist motion interference.

[0074] Effect Example 2 Application of High Elastic Hydrogel Fiber in Conductive Fiber

[0075] The highly elastic hydrogel fiber of Example 2 was connected to a wearable device (light belt) and worn on the wrist. Figure 7 It was found that when the wrist is bent or rotated, the brightness of the light strip does not change because the conductivity of the conductive fiber does not change. Therefore, the highly elastic hydrogel fiber can be used to prepare smart wearable devices that are resistant to motion interference.

[0076] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. Highly elastic hydrogel fiber with conductivity insensitive to stretching, characterized by: It comprises an outer shell and an inner core; the outer shell is composed of a polymer, and the inner core is composed of a blend of PEDOT:PSS, glutaraldehyde and polyvinyl alcohol; the outer shell and the inner core are coaxial; the amount of PEDOT:PSS added to the blend is 0.5 wt%-2.0 wt%; the amount of polyvinyl alcohol added is 1wt%-3wt%; the amount of glutaraldehyde added is 1.0μl / mL-4.0μl / mL; the polymer comprises polyurethane and / or silicone rubber.

2. The high-elastic hydrogel fiber according to claim 1, characterized in that: The outer diameter of the high-elastic hydrogel fiber is 0.5-2.0 mm.

3. The high-elastic hydrogel fiber according to claim 1, characterized in that: The concentration of the polymer is 160 mg / mL-240 mg / mL.

4. The method for preparing the highly elastic hydrogel fiber according to any one of claims 1 to 3, characterized in that: The steps include: S1. preparing microfluidic inner layer fluid: preparing a mixed solution of PEDOT:PSS, glutaraldehyde and polyvinyl alcohol as the microfluidic inner layer fluid; S2. Preparation of microfluidic middle layer fluid: Preparation of DMSO solution of polymer as microfluidic middle layer fluid; S3, preparing microfluidic outer layer fluid: preparing DMSO / H2O mixed solution as microfluidic outer layer fluid; S4. Preparation of highly elastic hydrogel fibers: respectively introducing the prepared microfluidic inner layer fluid, microfluidic middle layer fluid and microfluidic outer layer fluid into the inner, middle and outer phase channels of the microfluidic device to form a stable laminar flow structure in the outlet capillary to obtain the highly elastic hydrogel fibers.

5. The preparation method according to claim 4, characterized in that: The flow rate of the inner layer fluid in step S1 is 0.6-1.4 mL / h; the flow rate of the middle layer fluid in step S2 is 3-5 mL / h; and the flow rate of the outer layer fluid in step S3 is 30-50 mL / h.

6. The preparation method according to claim 4, characterized in that: In step S4, the channel structure of the microfluidic device is in the form of coaxial nesting of the inner phase channel and the outer phase channel.

7. Use of the highly elastic hydrogel fiber according to any one of claims 1 to 3 or the highly elastic hydrogel fiber prepared by the preparation method according to any one of claims 4 to 6 in the preparation of intelligent wearable textiles that are resistant to motion interference.

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