A ternary system coagulation bath and hydrogel fiber prepared therefrom

Abstract

The present invention discloses a ternary system coagulation bath and a prepared hydrogel fiber, belonging to the technical field of polymer hydrogels. The ternary system coagulation bath includes a hydrogen bond donor and a hydrogen bond acceptor with a molar ratio of not less than 1:1, and a reinforcing agent accounting for 0.5~2wt% of the total mass of the hydrogen bond donor and the hydrogen bond acceptor; the total content of the hydrogen bond donor and the hydrogen bond acceptor accounts for at least 70wt% of the ternary system coagulation bath; water balance; wherein the hydrogen bond donor is an organic small molecule containing a Lewis acidic site; the hydrogen bond acceptor is a metal organic complex containing a Lewis basic site; the reinforcing agent is one or more of graphene oxide, carbon nanotubes or poly (3,4-ethylenedioxythiophene)-poly (styrene sulfonic acid). The mechanical properties and electrical conductivity of the prepared hydrogel fiber are good, the breaking strength is not less than 0.4MPa, the elongation at break is not less than 190%, and the electrical conductivity is not less than 2S / m.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer hydrogels, and more particularly to a ternary system coagulation bath and the prepared hydrogel fibers. Background Art

[0002] Hydrogels are widely used in fields such as bioengineering and materials science due to their excellent biocompatibility and high water content. Hydrogels are mostly present in the form of blocks or films, but their size and shape are fixed. Compared to hydrogel blocks, hydrogel fibers have unique morphological and structural advantages, making them suitable for a wider range of applications.

[0003] Existing technologies for preparing hydrogel fibers rely primarily on chemical crosslinking or single-ion coagulation, which presents several drawbacks: a single coagulation bath mechanism and single function, making it difficult to achieve a balance between mechanical properties, high water content, and biological functionality. Furthermore, the process is complex, typically requiring multiple chemical crosslinking steps, UV curing, or high-temperature treatment, resulting in high equipment and process costs. In recent years, deep eutectic solvents (DESs) have gradually replaced traditional organic solvents (such as DMSO) and inorganic salt systems (such as CaCl2 / ethylene glycol) in fiber spinning coagulation baths due to their low toxicity, biodegradability, and designability. However, existing DES coagulation bath technology still faces several bottlenecks: limited functionality. Currently, mainstream DES systems (such as choline chloride / urea and choline chloride / ethylene glycol) focus primarily on basic solvent physicochemical properties (such as viscosity) and lack value-added features such as conductivity. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies or defects and to provide a ternary system coagulation bath, which can make the prepared hydrogel fiber have higher mechanical properties and conductivity through the synergistic effect of hydrogen bond acceptors, hydrogen bond donors and reinforcing agents.

[0005] Another object of the present invention is to provide an application of the ternary system coagulation bath.

[0006] Another object of the present invention is to provide a hydrogel fiber.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A ternary system coagulation bath comprising a hydrogen bond donor and a hydrogen bond acceptor in a molar ratio of not less than 1:1, and a reinforcing agent accounting for 0.5 to 2 wt% of the total mass of the hydrogen bond donor and the hydrogen bond acceptor; the total content of the hydrogen bond donor and the hydrogen bond acceptor accounts for at least 70 wt% of the ternary system coagulation bath; the balance is water;

[0009] The hydrogen bond donor is an organic small molecule containing a Lewis acidic site; the hydrogen bond acceptor is a metal organic complex containing a Lewis basic site; and the enhancer is one or more of graphene oxide, carbon nanotubes, or poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid).

[0010] The present invention provides a ternary system coagulation bath, which adopts a specific hydrogen bond acceptor, a hydrogen bond donor and a reinforcing agent in coordination, so that the prepared hydrogel fiber has good mechanical properties and conductivity. Specifically, the Lewis acidic site in the hydrogen bond donor can provide hydrogen bond protons to the hydrogen bond acceptor, and a stable and continuous hydrogen bond connection network can be constructed during the interaction between the Lewis acidic site and the hydrogen bond acceptor. At the same time, its flexible molecular skeleton allows the internal conformation to be adjusted on a microscopic scale, thereby improving the adaptability of the entire system to stress or structural perturbations, and helping to construct a composite solvent system with good viscoelasticity and outstanding energy dispersibility; the hydrogen bond acceptor is a metal organic complex containing a Lewis basic site, which can effectively attract and fix the hydrogen bond acceptor. In addition, the metal center contained in this type of hydrogen bond acceptor can guide the arrangement of the surrounding donor molecules, thereby forming a locally ordered aggregation area within the hydrogen bond network. The reversible complexation between the metal and the ligand also gives the network a certain degree of dynamic regulation ability, helping the material maintain structural integrity and achieve self-regulation of performance under changes in the external environment (such as temperature and shear). The reinforcing agent in the system itself does not participate in the chemical crosslinking of the main chain, but it can provide a high density of adsorption sites in the hydrogen bond network, thereby inducing spatial reconstruction of the network. This type of reinforcing component improves the structural density and stability of the network through non-covalent interactions with surrounding molecules, such as hydrogen bonding or interfacial adsorption, while also restricting chain segment motion to a certain extent, enhancing the rigidity of the system. The inventors unexpectedly discovered that the addition of a reinforcing agent to this system can improve the mechanical properties of the resulting hydrogel fiber while also improving its electrical conductivity.

[0011] It should be noted that the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor in the present invention is not less than 1:1, for example but not limited to not less than 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8 or 1:4, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0012] Furthermore, the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is 1:1 to 3:1.

[0013] It should be noted that the enhancer accounts for 0.5~2wt% of the total mass of the hydrogen bond donor and the hydrogen bond acceptor, for example, but not limited to 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2wt%, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the specific point values ​​included in the range are no longer exhaustively listed in the present invention.

[0014] It should be noted that the total content of the hydrogen bond donor and the hydrogen bond acceptor accounts for at least 70wt% of the ternary system coagulation bath, for example, but not limited to at least 70wt%, 72wt%, 75wt%, 78wt%, 80wt%, 82wt%, 85wt% or 90wt% of the ternary system coagulation bath, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the specific point values ​​included in the range are no longer exhaustively listed in the present invention.

[0015] Furthermore, the total content of the hydrogen bond donor and the hydrogen bond acceptor accounts for at least 70-85 wt % of the ternary system coagulation bath.

[0016] Furthermore, the hydrogen bond donor is one or more of levulinic acid, lactic acid, malic acid or citric acid.

[0017] Furthermore, the hydrogen bond acceptor is lactic acid and / or citric acid.

[0018] Furthermore, the hydrogen bond acceptor is one or more of zinc gluconate, calcium gluconate, magnesium gluconate, calcium lactate or zinc citrate.

[0019] Furthermore, the hydrogen bond acceptor is calcium lactate and / or zinc gluconate.

[0020] Furthermore, the reinforcing agent is graphene oxide.

[0021] In some preferred embodiments, the graphene oxide is a single-layer graphene oxide, and the graphene oxide has a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

[0022] The present invention also provides a method for preparing hydrogel fibers, comprising the following steps:

[0023] The spinning solution is extruded into the ternary system coagulation bath, and then subjected to heat consolidation, freeze strengthening and drying in sequence to obtain the product.

[0024] Furthermore, the spinning solution is one or more of a polyvinyl alcohol aqueous solution, a polyvinyl alcohol-sodium alginate aqueous solution or a polyvinyl alcohol-nanocellulose aqueous solution.

[0025] It should be noted that, when the spinning solution is a polyvinyl alcohol-sodium alginate aqueous solution, the ternary system coagulation bath further includes calcium chloride accounting for 3-8 wt % of the ternary system coagulation bath.

[0026] In some preferred embodiments, the mass concentration of the spinning solution is 8-15 wt %.

[0027] In some preferred embodiments, the degree of polymerization of the polyvinyl alcohol is 1600-1800.

[0028] In some preferred embodiments, the spinning solution is obtained by dissolving polyvinyl alcohol and sodium alginate at a mass ratio of 3:1 in water at 10 wt%, stirring at 80° C. for 30 minutes, and degassing at room temperature for 10 minutes.

[0029] In some preferred embodiments, the extrusion is performed by a syringe pump with a flow rate controlled at 0.1 mL / min and extruded through a 23G spinneret (inner diameter 0.42 mm).

[0030] Specifically, the extruder was aligned with the coagulation bath surface and the spinning distance was 5 mm.

[0031] Furthermore, the temperature of the ternary system coagulation bath is 20-25° C. When the spinning solution enters the coagulation bath after spinning, it can be instantly formed due to the hydrogen bonding effect in the ternary system coagulation bath.

[0032] Furthermore, the temperature of the thermal reinforcement is 37-60°C.

[0033] Specifically, the coagulated fiber is placed in a water bath at 37° C. and immersed for 5 minutes. At this temperature, the hydrogen bond donors further interact with the spinning solution segments to form a second-level physical network structure.

[0034] Furthermore, the freeze strengthening is specifically performed by freezing at -20°C for 2 hours and thawing at room temperature for 2 hours, and the cycle is repeated 2 to 4 times. After the freeze strengthening, the polyvinyl alcohol segments in the spinning solution undergo phase separation and microcrystallization, thereby constructing a third-level physical network structure.

[0035] Furthermore, the drying is performed by freeze drying or vacuum drying.

[0036] In some preferred embodiments, the freeze-strengthened fibers are rinsed to remove residual small molecules before drying.

[0037] Specifically, the freeze-drying temperature is -40°C, and the freeze-drying time is 24 hours.

[0038] Specifically, the vacuum drying temperature is 37° C., and the vacuum drying time is 12 h.

[0039] The present invention also provides a hydrogel fiber, which is prepared by adopting the above preparation method.

[0040] Specifically, the average diameter of the hydrogel fibers is 60-250 nm.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention provides a ternary system coagulation bath. By selecting specific hydrogen bond donors, hydrogen bond acceptors and enhancers as the coagulation bath for hydrogel fiber spinning, the mechanical properties and conductive properties of the prepared hydrogel fibers can be effectively improved, with a breaking strength of not less than 0.4 MPa, an elongation at break of not less than 190%, and an electrical conductivity of not less than 2 S / m. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a physical picture of the hydrogel fiber prepared in Example 4;

[0044] Figure 2 1 is a scanning electron microscope image of the hydrogel fibers prepared in Examples 1 to 6;

[0045] Figure 3 These are scanning electron microscope images of the hydrogel fibers prepared in Comparative Examples 1 and 2. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with specific embodiments, but the examples do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the examples of the present invention are conventionally purchased raw materials and reagents.

[0047] Polyvinyl alcohol: degree of polymerization 1700;

[0048] Graphene oxide: single-layer graphene oxide powder, MacLean's reagent.

[0049] Example 1

[0050] A method for preparing hydrogel fibers comprises the following steps:

[0051] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor lactic acid to the hydrogen bond acceptor zinc gluconate is 1:1, the graphene oxide accounts for 1 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, 5 wt% calcium chloride, and the balance water are mixed to obtain a ternary coagulation bath;

[0052] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0053] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0054] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0055] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0056] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0057] Example 2

[0058] A method for preparing hydrogel fibers comprises the following steps:

[0059] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor lactic acid to the hydrogen bond acceptor zinc gluconate is 2:1, graphene oxide accounts for 1 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, 5 wt% calcium chloride, and the balance water are mixed to obtain a ternary coagulation bath;

[0060] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0061] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0062] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0063] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0064] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0065] Example 3

[0066] A method for preparing hydrogel fibers comprises the following steps:

[0067] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor lactic acid to the hydrogen bond acceptor zinc gluconate is 3:1, the graphene oxide accounts for 1 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, 5 wt% calcium chloride, and the balance water are mixed to obtain a ternary coagulation bath;

[0068] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0069] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0070] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0071] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0072] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0073] Example 4

[0074] A method for preparing hydrogel fibers comprises the following steps:

[0075] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor lactic acid to the hydrogen bond acceptor zinc gluconate is 3:1, the graphene oxide accounts for 2 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, 5 wt% calcium chloride, and the balance water are mixed to obtain a ternary coagulation bath;

[0076] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0077] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0078] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0079] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0080] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules and freeze-dried at -40 ° C for 24 h to obtain hydrogel fibers (see the actual figure). Figure 1 ).

[0081] Example 5

[0082] A method for preparing hydrogel fibers comprises the following steps:

[0083] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor citric acid to the hydrogen bond acceptor zinc gluconate is 2:1, the graphene oxide accounts for 1 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, 5 wt% calcium chloride, and the balance water are mixed to obtain a ternary coagulation bath;

[0084] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0085] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0086] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0087] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0088] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0089] Example 6

[0090] A method for preparing hydrogel fibers comprises the following steps:

[0091] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor citric acid to the hydrogen bond acceptor zinc citrate is 2:1, the graphene oxide accounts for 1 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, 5 wt% calcium chloride, and the balance water are mixed to obtain a ternary coagulation bath;

[0092] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0093] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0094] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0095] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0096] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0097] Example 7

[0098] A method for preparing hydrogel fibers comprises the following steps:

[0099] S1. Ternary coagulation bath: The molar ratio of the hydrogen bond donor lactic acid to the hydrogen bond acceptor zinc gluconate is 2:1, the graphene oxide accounts for 1 wt% of the total mass of the hydrogen bond donor and hydrogen bond acceptor, the hydrogen bond donor and hydrogen bond acceptor account for 80 wt% of the ternary coagulation bath, and the balance is water, and the mixture is uniformly mixed to obtain a ternary coagulation bath;

[0100] S2. Spinning solution preparation: Dissolve polyvinyl alcohol in water at a concentration of 10 wt%, stir at 80°C for 30 min, and degas at room temperature for 10 min to obtain the spinning solution;

[0101] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min. The solution was extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the ternary coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0102] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0103] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0104] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0105] Comparative Example 1

[0106] A method for preparing hydrogel fibers comprises the following steps:

[0107] S1. Coagulation bath: The molar ratio of hydrogen bond donor glycerol and hydrogen bond acceptor choline chloride is 1:1, the hydrogen bond donor and hydrogen bond acceptor account for 80wt% of the coagulation bath, 5wt% calcium chloride, and the balance of water are mixed to obtain a coagulation bath;

[0108] S2. Spinning solution preparation: Spinning solution preparation: Polyvinyl alcohol-sodium alginate with a mass ratio of 3:1 was dissolved in water at a concentration of 10 wt%, stirred at 80 ° C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0109] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min and extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0110] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0111] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0112] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0113] Comparative Example 2

[0114] A method for preparing hydrogel fibers comprises the following steps:

[0115] S1. Coagulation bath: The molar ratio of hydrogen bond donor glycerol and hydrogen bond acceptor choline chloride is 1:1, graphene oxide is 1wt% of the total mass of hydrogen bond donor and hydrogen bond acceptor, hydrogen bond donor and hydrogen bond acceptor account for 80wt% of the coagulation bath, 5wt% calcium chloride, and the balance water are mixed to obtain a coagulation bath;

[0116] S2. Spinning solution preparation: Polyvinyl alcohol-sodium alginate (3:1 by mass) was dissolved in water at a concentration of 10 wt%, stirred at 80°C for 30 min, and degassed at room temperature for 10 min to obtain a spinning solution;

[0117] S3. Wet spinning: The spinning solution from step S2 was placed in a syringe pump at a flow rate of 0.1 mL / min and extruded through a 23G spinneret (0.42 mm inner diameter) aligned with the surface of the coagulation bath (controlled at 22°C) from step S1 at a distance of 5 mm.

[0118] S4. Thermal consolidation: The fibers solidified in step S3 were immersed in a 37°C water bath for 5 min;

[0119] S5. Freeze-strengthening: The fiber obtained in step S4 was frozen at -20 ° C for 2 h, thawed at room temperature for 2 h, and the cycle was repeated 3 times;

[0120] S6. Post-treatment and drying: The fibers treated in step S5 were washed three times to remove residual small molecules, and freeze-dried at -40°C for 24 hours to obtain hydrogel fibers.

[0121] Performance Testing

[0122] 1. Test method

[0123] (1) Morphology characterization test

[0124] The surface morphology of the hydrogel fibers was observed using a scanning electron microscope (SEM, Hitachi, SU 5000). The fibers were first cut into uniform 2 mm segments and fixed on the stage using conductive glue. After gold spraying, the surface morphology of the samples was observed using a scanning electron microscope (see Figure 2 and Figure 3 ).

[0125] (2) Mechanical properties test

[0126] An electronic universal testing machine (CMT610, Meters Industries, China) was used to test the mechanical properties of the hydrogel fibers. A vernier caliper was used to measure the diameter of the hydrogel fibers. The length of the hydrogel sample was 5 cm, and the test speed was 80 mm / min. The hydrogel fibers were subjected to a cyclic tensile test, and the elongation at break and breaking strength were recorded. Each hydrogel fiber was measured three times and the average value was taken.

[0127] (3) Conductivity test

[0128] Take 1cm long hydrogel fiber and use electrochemical workstation at 10 0 -10 5 The resistance of the hydrogel fiber was measured in the frequency range of Hz, and the conductivity was calculated according to σ=L / RS;

[0129] Where: L is the length of the sample, cm; R is the measured resistance value, Ω; S represents the effective cross-sectional area of ​​the hydrogel fiber, cm 2 .

[0130] 2. Test results

[0131] The test results of the hydrogel fibers of the above embodiments and comparative examples are shown in Tables 1 and Figures 1-3 As shown; Figure 2 (a) to (f) correspond to the scanning electron micrographs of the hydrogel fibers prepared in Examples 1 to 6, respectively; Figure 3 (a) and (b) are scanning electron microscope images of the hydrogel fibers prepared in Comparative Example 1 and Comparative Example 2, respectively.

[0132] Table 1 Test results of various embodiments and comparative examples

[0133]

[0134] As can be seen from Table 1, the hydrogel fiber produced using the coagulation bath of the present invention has good mechanical properties and conductive properties. Specifically, the produced hydrogel fiber has a breaking strength of not less than 0.4 MPa, an elongation at break of not less than 190%, and an electrical conductivity of not less than 2 S / m.

[0135] It can be seen from Examples 1 to 3 that as the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor in the coagulation bath increases, the mechanical properties and the conductive properties of the prepared hydrogel fibers are gradually enhanced.

[0136] It can be seen from Comparative Examples 1 and 2 that if a traditional low eutectic solvent is used or a reinforcing agent is added to a traditional low eutectic solvent, the resulting hydrogel fibers have significantly poorer electrical conductivity and mechanical properties than those in the examples.

[0137] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A ternary system coagulation bath, characterized in that: The invention comprises a hydrogen bond donor and a hydrogen bond acceptor in a molar ratio of not less than 1:1, and a reinforcing agent accounting for 0.5 to 2 wt% of the total mass of the hydrogen bond donor and the hydrogen bond acceptor; the total content of the hydrogen bond donor and the hydrogen bond acceptor accounts for at least 70 wt% of the ternary system coagulation bath; the balance is water; Wherein, the hydrogen bond donor is lactic acid and / or citric acid; the hydrogen bond acceptor is one or more of zinc gluconate, zinc citrate or calcium gluconate; and the enhancer is graphene oxide.

2. The ternary system coagulation bath according to claim 1, characterized in that: The total content of the hydrogen bond donor and the hydrogen bond acceptor accounts for 70-85 wt % of the ternary system coagulation bath.

3. The ternary system coagulation bath according to claim 1, characterized in that: The molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is 1:1 to 3:

1.

4. The ternary system coagulation bath according to claim 1, characterized in that: The ternary system coagulation bath further includes calcium chloride accounting for 3-8 wt % of the ternary system coagulation bath.

5. A method for preparing hydrogel fiber, characterized in that: The steps include: The spinning solution is extruded into the ternary system coagulation bath according to any one of claims 1 to 4, and then subjected to heat consolidation, freeze strengthening and drying in sequence to obtain the spinning solution.

6. The preparation method according to claim 5, characterized in that: The spinning solution is one or more of a polyvinyl alcohol aqueous solution, a polyvinyl alcohol-sodium alginate aqueous solution, or a polyvinyl alcohol-nanocellulose aqueous solution; the temperature of the ternary system coagulation bath is 20-25°C; the temperature of the thermal consolidation is 37-60°C; and the freeze strengthening is specifically freezing at -20°C for 2 hours, thawing at room temperature for 2 hours, and repeating 2-4 times.

7. A hydrogel fiber, characterized in that: The preparation method according to claim 5 or 6 is used.

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