CN115819684A

CN115819684A - Multifunctional ionic conductive high-toughness hydrogel and preparation method and application thereof

Info

Publication number: CN115819684A
Application number: CN202211493604.5A
Authority: CN
Inventors: 王荣; 左振霖
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS; Cixi Institute of Biomedical Engineering CIBE of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS; Cixi Institute of Biomedical Engineering CIBE of CAS
Priority date: 2022-11-25
Filing date: 2022-11-25
Publication date: 2023-03-21

Abstract

The application discloses a multifunctional ionic conduction type high-toughness hydrogel as well as a preparation method and application thereof, belonging to the field of high-molecular hydrogels. An ionic conduction type hydrogel comprises a zwitterionic polymer and phytic acid; the ionic conduction type hydrogel is of a dual network structure; polymerizing the zwitterions with each other to form a first heavy network structure; the phytic acid and the zwitterionic polymer form a second cross-linked network through non-covalent interaction. The electric conductivity of the hydrogel can reach 2.44S/m at most, the strain coefficient (GF) can reach 9.7 at most, and the electric conductivity is improved by two orders of magnitude compared with that of the poly-zwitter-ion hydrogel of a control group.

Description

Multifunctional ionic conductive high-toughness hydrogel and preparation method and application thereof

Technical Field

The application relates to a multifunctional ionic conductive high-toughness hydrogel and a preparation method and application thereof, belonging to the field of high-molecular hydrogels.

Background

In recent years, conductive hydrogels have been developed in the fields of wearable sensors, artificial muscles, and electronic skins, etc. due to the characteristics of excellent mechanical properties and stability, high sensitivity, and stable conductive properties. The conversion of mechanical signals of human activity into electrical signals depends on the electrical properties of the conductive hydrogel. Among them, electrical conductivity has been widely noticed and studied as an important property for measuring electrical properties of flexible sensors.

The conductive hydrogel can be classified into an electron conductive hydrogel and an ion conductive hydrogel according to a transfer medium. In the former method, the conductivity of the hydrogel is improved by doping conductive fillers (such as metal nano materials, conductive carbon or carbide/nitride nano materials, graphene and the like) or introducing conductive polymers (such as polypyrrole, polyaniline, PEDOT and the like) into the system. However, both the aggregation or random distribution of the filler and the hardness of the conductive polymer can result in a decrease in gel ductility, recovery, and conductivity. Since such gels transport electrical signals through electrons and holes, the electrical behavior of the system is easily affected by changes in the internal network structure. When the gel bears large strain, the network structure in the gel is easy to damage, and the system loses the conductive capability. On the other hand, when the electronic conductive hydrogel is applied to human physiological signal detection, the electronic conductive hydrogel often shows poor biocompatibility. In addition, electronic conductors tend to be opaque, which also poses obstacles to the manufacture and use of flexible and wearable devices. Ion-conducting hydrogels generally consist of three substrates: water, polymers, and ionic conductors. The water in the hydrogel can provide a reliable path for the transmission of ionic conductors in the system, and the polymers are connected into a three-dimensional network structure through chemical or physical interaction, so that mechanical structural support is provided for the hydrogel. Compared with the electronic conductive hydrogel, the flexible and wearable device prepared from the ionic conductive hydrogel has a wider strain detection range, better conductivity, high transparency and good biocompatibility.

While many advances and developments have been made in ionically conductive hydrogels, it remains a challenge to prepare hydrogels having desirable mechanical properties (e.g., tensile strength, extensibility, toughness, and resiliency, etc.) and high electrical conductivity. To date, the preparation of conventional ion-conducting hydrogels essentially comprises two steps: (1) preparing traditional tough hydrogel as a carrier material; (2) The hydrogel network is loaded with an electrolyte to increase the conductivity of the material by soaking in a high concentration salt solution. However, the internal network structure of the strong hydrogel is damaged by soaking in the salt solution, so that the mechanical property and the adhesion property of the system are sacrificed while the conductivity is improved. In addition, the complicated preparation process also increases the investment of energy and time cost, resulting in a great deal of resource waste.

In biological applications, electrically conductive hydrogel materials need to integrate high electrical conductivity and good mechanical properties to be compatible with human tissue (e.g., skin, muscle, heart or brain) for long periods of time. In addition, in practical application scenarios, other important parameters should be considered, such as: when the conductive hydrogel is used as a flexible sensor, the conductive hydrogel needs to be attached to the surface of a tissue; when the material is used on the surface of traumatic skin or after operation, the material needs to have antibacterial performance, so that the invasion and infection of pathogenic microorganisms to human tissues are avoided; the material needs to have certain anti-freezing performance and can meet the application requirement of the material in low-temperature environment.

Therefore, it is important to search for a simple, low-cost and easy-to-process method for preparing a multifunctional conductive hydrogel which is matched with tissue properties and is stable.

Disclosure of Invention

According to a first aspect of the present application, an ion-conductive hydrogel with high toughness is provided, wherein the ion-conductive hydrogel utilizes polymerization of zwitterionic monomers to form a first heavy crosslinked network, and a second heavy crosslinked network is constructed through addition of phytic acid. Wherein the first heavy cross-linked network is formed by covalent bond formation and electrostatic interaction between zwitterionic monomers; the second crosslinked network is formed by hydrogen bond and electrostatic interaction formed by phytic acid and zwitterionic polymers. The selected zwitterionic polymer has excellent adhesiveness, can realize adhesion on the surfaces of different materials, and has adhesion universality; the added phytic acid enhances the gel network and improves the adhesion performance, and simultaneously introduces a large amount of free hydrogen ions into the system through the ionization of phosphate radicals, so that the hydrogel has excellent conductivity.

The ionic conduction type high-toughness hydrogel obtained by the method has excellent antibacterial performance, can damage the structural integrity of the wound through the interaction with a bacterial cell membrane when acting on the wound so as to achieve the antibacterial purpose, prevents the further injury of the wound and the invasion of bacteria, reduces pain and saves medical cost. The ionic conductive high-toughness hydrogel has various mechanical properties, adhesion property, conductivity, antibacterial property and freezing resistance which can be subjectively regulated and controlled by adjusting the relative content of phytic acid and a zwitter-ion structural unit and reaction conditions.

The conductive hydrogel integrates antibacterial property, self-adhesion property, high light transmittance, stress strain sensing performance and frost resistance, and can be used as various flexible wearable devices and wound dressings. The conductive hydrogel forms a cross-linked network structure of gel through polymerization of zwitterionic monomers. The added phytic acid provides freely movable ions in the gel through dissociation to endow the hydrogel with excellent conductivity; on the other hand, the gel can enhance the mechanical property and the adhesion property of the gel through electrostatic interaction with the zwitter-ion group and the skin tissue surface group. In addition, the bacteria are killed through the interaction with the bacteria, so that the aim of antibiosis is fulfilled; the hydrogel is endowed with excellent anti-freezing performance by forming strong hydrogen bond action with water molecules. The skilled person can determine it autonomously within the scope defined by the present application depending on the actual application scenario.

The ionic conductive high-toughness hydrogel is composed of two functional components: the first component is one which provides excellent mechanical properties and self-adhesive properties; the second group imparts antimicrobial, antifreeze and conductivity properties to the hydrogel. The two components are combined through various non-covalent bond forces to improve the overall performance of the material, so that the prepared hydrogel integrates the characteristics of conductive sensing, antibiosis, frost resistance, self adhesion and the like.

An ion-conducting hydrogel comprising a zwitterionic polymer, phytic acid;

the ionic conduction type hydrogel is of a dual network structure;

polymerizing the zwitterions with each other to form a first heavy network structure;

the phytic acid and the zwitterionic polymer form a second cross-linked network through non-covalent interaction.

Optionally, the ionically conductive hydrogel is comprised of a three-dimensional network structure and a continuous aqueous phase.

Alternatively, covalent and electrostatic interactions between the zwitterionic units.

Optionally, the zwitterionic polymer forms dipole-dipole interactions and hydrogen bonding interactions with the tissue interface to effect adhesion.

Alternatively, the zwitterionic units contain both cationic and anionic charges on the same macromolecular chain.

Alternatively, the phytic acid dissociates free hydrogen ions under acidic conditions.

Alternatively, the phytic acid forms ionic and hydrogen bond interactions with the groups of the zwitterionic units.

Alternatively, the phosphate group in the phytic acid forms a hydrogen bond with a water molecule.

The phytic acid disrupts the structural integrity of the bacteria by interacting with the bacterial cell membrane.

Optionally, the zwitterionic monomer is selected from at least one of methacryloyl ethyl sulfobetaine, 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate, 2- ((3-acrylamidopropyl) dimethylammonium) acetate, 2-methacryloyloxyethyl phosphorylcholine.

Optionally, the water content in the ionic conduction type hydrogel is 0.36 to 0.61.

Optionally, the molar ratio of the zwitterionic polymer in the ionic conduction type hydrogel is 0.67-0.95.

Optionally, the molar ratio of the phytic acid in the ion-conductive hydrogel is 0.04 to 0.33.

The zwitterionic monomer, when polymerized, provides a polymer network structure: on one hand, under the action of an initiator and a cross-linking agent, a network structure of hydrogel can be formed through free radical polymerization of a zwitterionic monomer; on the other hand, the strength of the network is enhanced by electrostatic interaction between the zwitterionic units.

The zwitterionic monomer provides an environment rich in ionic components: on one hand, the hydrogel is composed of a three-dimensional network structure and a continuous water phase, and can provide a large number of channels for ion migration; on the other hand, the polyamphiphilic ions simultaneously contain cationic charges and anionic charges on the same macromolecular chain, so that a network structure rich in charge units can be constructed.

The zwitterionic units provide the gel with adhesive properties: can form dipole-dipole interaction and hydrogen bond interaction with a tissue interface to realize adhesion, and has certain universal adhesion.

The phytic acid is used as an ionic cross-linking agent, and forms the interaction of ionic bonds and hydrogen bonds with zwitterionic groups, so that the mechanical property of the material is enhanced.

The dissociation of the phytic acid generates a large amount of free hydrogen ions, and the high ionic conductivity is endowed to the hydrogel through the coordination of the free hydrogen ions and the charged groups of the zwitter-ion component.

The phytic acid improves the freezing resistance: a large amount of phosphate groups rich in phytic acid can form strong hydrogen bond action with water molecules, evaporation and crystallization of water in a system are weakened, and excellent anti-freezing performance is achieved.

The phytic acid can destroy the structural integrity of the phytic acid through interaction with bacterial cell membranes so as to achieve the antibacterial purpose, prevent further injury of wounds and invasion of bacteria, reduce pain and save medical cost.

Optionally, the molar ratio of the zwitterionic monomer polymer in the ionic conduction type hydrogel is independently selected from any of 0.67, 0.73, 0.79, 0.85, 0.91, 0.95 or a range between any two.

Optionally, the molar ratio of the phytic acid in the ion-conducting hydrogel is independently selected from any of 0.04, 0.11, 0.18, 0.25, 0.31, 0.33, or a range between any two.

Optionally, the water content in the ionically conductive hydrogel is independently selected from any of 0.36, 0.38, 0.40, 0.42, 0.44, 0.46, 0.48, 0.50, 0.52, 0.54, 0.56, 0.58, 0.60, 0.61 or a range between any two.

According to the second aspect of the application, the preparation method of the ionic conduction type hydrogel is simple in process and controllable in operation, can be realized by only carrying out free radical polymerization on a zwitterionic monomer and phytic acid in the presence of a small amount of an initiator and a chemical cross-linking agent, is quick to prepare, is low in cost, and is easy to put into large-scale industrial production.

A preparation method of ionic conduction type hydrogel comprises the following steps:

s1, stirring a mixed solution containing a zwitterion monomer, phytic acid, an initiator and a chemical cross-linking agent to obtain a gel pre-polymerization solution;

s2, injecting the gel pre-polymerization liquid into a mold, and carrying out ultraviolet curing or heating to obtain the ion conductive hydrogel.

Optionally, in the step S1, the rotation speed of stirring is not lower than 750r/min.

Optionally, in step S1, the concentration of the phytic acid is 0.1mol/L to 1mol/L.

Optionally, the concentration of phytic acid is independently selected from any of 0.1mol/L, 0.2mol/L, 0.3mol/L, 0.4mol/L, 0.5mol/L, 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1.0mol/L, or a range between any two.

Optionally, the phytic acid concentration is 0.6mol/L.

Optionally, in step S1, the concentration of the zwitterionic monomer is 2.0mol/L to 4.2mol/L.

Optionally, the concentration of the zwitterionic monomer is independently selected from any of 2.0mol/L, 3mol/L, 3.2mol/L, 3.4mol/L, 3.6mol/L, 3.8mol/L, 4mol/L, 4.2mol/L or a range between any two.

Optionally, the concentration of the zwitterionic monomer is 4mol/L.

Optionally, in step S1, the initiator includes at least one of a photoinitiator and a thermal initiator.

Optionally, in step S1, the photoinitiator is selected from at least one of 2-hydroxy-2-methyl propiophenone, 2-oxoglutarate, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-propanone.

Optionally, in step S1, the thermal initiator is at least one selected from potassium persulfate, ammonium persulfate, and sodium persulfate.

Optionally, in step S1, the chemical crosslinker is selected from at least one of polyethylene glycol diacrylate, N-methylene bisacrylamide, polyethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethyleneoxy polyethylene glycol (meth) acrylate, 6,6 '-diamino-3,3' -methylene dibenzoic acid.

Optionally, the concentration of the initiator is 0.002mol/L to 0.02mol/L.

Alternatively, the concentration of the initiator is independently selected from any of 0.002mol/L, 0.004mol/L, 0.006mol/L, 0.008mol/L, 0.009mol/L, 0.010mol/L, 0.011mol/L, 0.012mol/L, 0.013mol/L, 0.014mol/L, 0.015mol/L, 0.016mol/L, 0.018mol/L, 0.02mol/L, or a range between any two.

Optionally, the concentration of the initiator is 0.012mol/L.

Optionally, in step S1, the concentration of the chemical crosslinking agent is 0.002mol/L to 0.02mol/L.

Optionally, the concentration of the chemical crosslinker is independently selected from any of 0.002mol/L, 0.004mol/L, 0.006mol/L, 0.008mol/L, 0.009mol/L, 0.010mol/L, 0.011mol/L, 0.012mol/L, 0.013mol/L, 0.014mol/L, 0.015mol/L, 0.016mol/L, 0.018mol/L, 0.02mol/L, or a range between any two.

Optionally, the concentration of the cross-linking agent is 0.012mol/L.

Alternatively, in step S2, the conditions of uv curing are as follows:

the time is 10min to 45min.

Optionally, in step S2, the wavelength of the ultraviolet light is 200nm to 420nm.

Alternatively, in step S2, the heating conditions are as follows:

the temperature is 55-85 ℃;

the time is 18-24 h.

Optionally, the conditions of the ultraviolet curing (radical polymerization) are: curing for 20min under the irradiation of ultraviolet light with the wavelength of 365nm in the presence of a cross-linking agent and a photoinitiator.

Alternatively, the conditions of the heating (radical polymerization) are: in the presence of a cross-linking agent and a thermal initiator, the temperature of the water bath is 65 ℃, and the water bath polymerization is carried out for 20 hours.

Optionally, the method comprises the following steps:

a1, uniformly dissolving a zwitterionic monomer in water to obtain a zwitterionic monomer dispersion liquid;

a2, adding a mixture containing phytic acid, a cross-linking agent and an initiator into the zwitterionic monomer dispersion liquid, and mixing to obtain a gel pre-polymerization liquid;

and A3, injecting the gel pre-polymerization liquid into a forming mold, and carrying out free radical polymerization reaction to obtain the ionic conduction type hydrogel.

According to a third aspect of the present application, there is provided use of an ionic conduction type hydrogel.

The ionic conduction type hydrogel and/or the ionic conduction type hydrogel obtained by the preparation method are applied to flexible wearable devices and wound dressings.

The flexible wearable device includes: limb movement monitoring, stress-strain distribution monitoring, human tissue movement detection, artificial intelligence and other related fields.

According to one embodiment of the present application, the method for preparing the phytic acid composite zwitterionic polymer hydrogel at least comprises the following steps:

(1) Fully dissolving the zwitterionic monomer into water by an ultrasonic and stirring method, wherein the mass concentration of the added zwitterionic monomer is 4mol/L;

(2) Adding phytic acid into the prepared aqueous solution of the zwitterionic monomer, mixing, then adding 0.012mol/L of cross-linking agent and 0.012mol/L of initiator, uniformly mixing until the solution is clear, and obtaining gel pre-polymerization liquid;

(3) And (3) injecting the gel pre-polymerization liquid obtained in the step (2) into a forming die, and carrying out free radical polymerization reaction to obtain the multifunctional ionic conduction type high-toughness hydrogel.

The beneficial effect that this application can produce includes:

1) The multifunctional ionic conductive high-toughness hydrogel provided by the application uses the zwitterionic polymers to construct a main body network of the hydrogel, the selected zwitterionic polymers are excellent in adhesion, adhesion can be realized on the surfaces of different materials, the hydrogel has adhesion universality, and the addition of phytic acid can enhance the adhesion capability of the hydrogel while endowing the hydrogel with conductive performance, so that the comprehensive improvement of the conductive performance and the adhesion performance is realized; the adhesion strength of the adhesive on the surface of the pigskin can reach 21.5kPa to the maximum extent, and is improved by 1 time; it can achieve a visible light transmittance of more than 90% in the visible light range (780-400 nm); can resist low temperature of-50 deg.C.

2) The multifunctional ionic conductive high-toughness hydrogel provided by the application forms a first heavy polymer network by utilizing the polymerization of a zwitterionic monomer, the added phytic acid enhances the polymerization structure of the gel network through hydrogen bonds, electrostatic interaction and the like, so that various mechanical properties are improved, the elongation at break can reach 422% to the maximum, the tensile strength can reach 333kPa to the maximum, and the strength is improved by 3 times compared with that of a group without the phytic acid; the maximum compression strength can reach 4.22MPa, and the strength is improved by 2 times compared with that of a group without phytic acid. Meanwhile, a large amount of freely movable ions are introduced into the system by adding phytic acid and ionizing phosphate radicals, so that the electric conductivity of the hydrogel is further improved; the maximum conductivity of the hydrogel can reach 2.44S/m, the maximum strain coefficient (GF) can reach 9.7, and the conductivity is improved by two orders of magnitude compared with that of a control group of the polyampholyte hydrogel.

3) The multifunctional ion-conductive high-toughness hydrogel has excellent antibacterial performance, can be acted on a wound to destroy the structural integrity of the wound through interaction with a bacterial cell membrane so as to achieve the antibacterial purpose, prevents further injury of the wound and invasion of bacteria, reduces pain and saves medical cost.

4) The preparation method of the multifunctional ionic conductive high-toughness hydrogel is simple in process and controllable in operation, can be realized by only carrying out free radical polymerization on a zwitterionic monomer and phytic acid in the presence of a small amount of initiator and chemical cross-linking agent, is quick to prepare, is low in cost, and is easy to put into large-scale industrial production.

5) The multifunctional ionic conductive high-toughness hydrogel provided by the application has various mechanical properties, adhesion properties, conductivity, antibacterial properties and freezing resistance, and can be subjectively regulated and controlled by adjusting the relative content of phytic acid and a zwitterionic monomer structural unit and reaction conditions.

Drawings

FIG. 1 is a schematic diagram of the tensile properties of the ionic conduction type high strength and toughness hydrogel.

FIG. 2 is a schematic diagram of the compressive properties of the ion-conducting high-toughness hydrogel of the present application.

FIG. 3 is a schematic diagram of the adhesion performance of the ion-conductive high-toughness hydrogel.

FIG. 4 is a schematic diagram of the conductivity of the ion-conducting type high-toughness hydrogel.

FIG. 5 is a graph showing the relative resistance change rate and the change of the strain coefficient (GF) of the ion-conductive high-toughness hydrogel according to the present application.

FIG. 6 is a transmittance spectrum of the ion-conducting high toughness hydrogel in the visible light range.

FIG. 7 is a schematic diagram of the antibacterial performance of the ion-conductive high-toughness hydrogel of the present application, wherein a is Escherichia coli; b is staphylococcus aureus.

FIG. 8 is a thermal response curve of the ionic conduction type high strength and toughness hydrogel of the present application.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified.

The analysis method in the examples of the present application is as follows:

the conductivity of the hydrogel was tested using a four-probe tester (Jiangsu lattice).

All mechanical property tests and adhesion property tests of the hydrogel are carried out by utilizing a universal tester (Sagitaijie).

The thermal response curve of the hydrogel was measured by a Differential Scanning Calorimeter (DSC) of DSC2500 of TA instruments, USA.

The inhibition effect of the hydrogel on gram-positive bacteria (such as staphylococcus aureus (S. Aureus)) and gram-negative bacteria (such as escherichia coli (E. Coli)) is researched by utilizing an inhibition zone experiment.

Example 1

(1) The methacryloylethylsulfobetaine (SBMA) monomer with a substance amount concentration of 4mol/L was sufficiently dissolved in water by a method of ultrasonic, stirring (750 r/min).

(2) Adding phytic acid with the amount concentration of 0.1, 0.2, 0.4, 0.6, 0.8 and 1.0mol/L into the prepared aqueous solution of the zwitterionic monomer, mixing, adding 0.012mol/L polyethylene glycol diacrylate and 0.012 mol/L2-hydroxy-2-methyl propiophenone, uniformly mixing until the solution is clear, and obtaining the gel pre-polymerization liquid.

(3) And (3) injecting the gel pre-polymerization solution obtained in the step (2) into a forming die, and curing for 20min under the ultraviolet irradiation with the wavelength of 365nm to obtain the multifunctional ion conduction type high-toughness hydrogel which is named as SP-1, SP-2, SP-4, SP-6, SP-8 and SP-10 respectively.

The multifunctional ionic conduction type high-toughness hydrogel prepared shows different mechanical properties, adhesion properties, antibacterial properties and conductivity due to the difference of ionic concentration.

Example 2

The preparation method was the same as example 2 except that the zwitterionic monomer of methacryloylethyl Sulfobetaine (SBMA) was replaced with 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate (CBMA) at a concentration of 4mol/L, and the hydrogel thus prepared was named as CP-x (x is a different content of phytic acid) hydrogel in the same manner as described above.

The CP series hydrogel prepared by the method shows similar change trend with the SP series hydrogel prepared in example 1 in the aspects of mechanical property, antibacterial property and conductivity.

Example 3

(1) A methacryloylethylsulfonobetaine (SBMA) monomer was sufficiently dissolved in water at a concentration of 4mol/L as a substance by means of sonication and stirring.

(2) Adding 0.1mol/L phytic acid into the prepared aqueous solution of the zwitterionic monomer, mixing, then adding 0.012mol/L polyethylene glycol diacrylate and 0.012mol/L ammonium persulfate, uniformly mixing until the solution is clear, and obtaining the gel pre-polymerization solution.

(3) Injecting the gel pre-polymerization liquid obtained in the step (2) into a forming die, and polymerizing for 20 hours in a water bath under the condition that the water bath temperature is 65 ℃.

The hydrogel prepared as described above had nearly the same mechanical properties and electrical conductivity as the SP-series hydrogel obtained in example 1.

Comparative example 1

(1) The amount concentration of the substance is 4mol/L, and the methacryl sulfonic acid betaine (SBMA) monomer is fully dissolved in water by a method of ultrasonic and stirring for 750r/min.

(2) Adding no phytic acid into the prepared aqueous solution of the zwitterionic monomer, adding 0.012mol/L of polyethylene glycol diacrylate and 0.012mol/L of 2-hydroxy-2-methyl propiophenone, and uniformly mixing until the solution is clear to obtain a gel pre-polymerization solution.

(3) And (3) injecting the gel pre-polymerization liquid obtained in the step (2) into a forming die, and curing for 20min under the ultraviolet irradiation with the wavelength of 365nm to obtain the multifunctional ion conductive high-strength and toughness hydrogel which is named as SP-0.

A series of representations of mechanical property, adhesion property, conductivity, antibacterial property and freezing resistance are also carried out on the hydrogel prepared by the method, and the results are summarized.

Comparative example 2

MP hydrogel was prepared using cationic monomer Methacryloyloxyethyl Trimethyl Ammonium Chloride (MTAC) complexed with phytic acid, as follows:

(1) The monomer of Methacryloyloxyethyl Trimethyl Ammonium Chloride (MTAC) with the mass concentration of 4mol/L is fully dissolved in water by the method of ultrasonic and stirring for 750r/min.

(2) Adding phytic acid with the amount concentration of 0.6mol/L, N' -methylene bisacrylamide with the amount concentration of 0.012mol/L and 2-hydroxy-2-methyl propiophenone with the amount concentration of 0.012mol/L into the prepared monomer aqueous solution, and uniformly mixing until the solution is clear to obtain the gel pre-polymerization solution.

(3) And (3) injecting the gel pre-polymerization liquid obtained in the step (2) into a forming die, curing for 60min under the ultraviolet irradiation with the wavelength of 365nm to form hydrogel, and naming the hydrogel as MP-6.

Comparative example 3

The AP hydrogel is prepared by compounding an anionic monomer 2-acrylamido-2-methylpropanesulfonic Acid (AMPS) and phytic acid, and the operation is as follows:

(1) Fully dissolving 2-acrylamide-2-methyl propanesulfonic Acid (AMPS) monomer with the mass concentration of 4mol/L in water by a method of ultrasonic and stirring for 750r/min.

(2) Adding phytic acid with the amount concentration of 0.6mol/L, polyethylene glycol diacrylate with the amount concentration of 0.012mol/L and 2-hydroxy-2-methyl propiophenone with the amount concentration of 0.012mol/L into the prepared monomer aqueous solution, and uniformly mixing until the solution is clear to obtain gel pre-polymerization liquid.

(3) And (3) injecting the gel pre-polymerization liquid obtained in the step (2) into a forming die, curing for 20min under the ultraviolet irradiation with the wavelength of 365nm to form hydrogel, and naming the hydrogel as AP-6.

Using a universal tester (Sagitaijie) to carry out tensile mechanical property test on the prepared MP-6 and AP-6 hydrogel, repeating the test for three times to obtain the MP-6 hydrogel with the tensile stress of 9.8kPa and the elongation at break of 380.6%; the tensile stress of the AP-6 hydrogel is 17.0kPa, the elongation at break is 183.6%, and the requirements of preparing a flexible sensor cannot be met. Comparing the performance of SP series hydrogel, the mechanical strength of the hydrogel prepared from cationic monomer or anionic monomer is far less than that of hydrogel prepared from zwitterion under the same preparation condition.

Comparative example 4

A methacrylyl Sulfonate Betaine (SBMA) monomer having a mass concentration of 4mol/L was mixed with the aqueous solution by only stirring at a rotation speed of 750r/min.

After stirring for 10min, the methacryl sulfonic acid betaine is found to not form a uniform liquid system, partial monomers are difficult to dissolve, the solution has undergone self-polymerization of partial monomers, and subsequent experimental operations cannot be continued.

Analytical example 1

A series of the SP, CP hydrogels prepared in examples 1, 2, and 3 above, as well as the SP-0 hydrogel of comparative example 1, were subjected to mechanical property tests, including tensile property test and compression property test, using a universal testing machine (Sagitatei). For the tensile test: the hydrogels were made into dumbbell-shaped test specimens of the same size and tested for tensile properties at a crosshead speed of 100mm/min until breakage, as shown in figure 1. For the compression test: the hydrogel was cut into cylinders of consistent size and thickness and compressed at a rate of 10% strain per minute to 90% strain as shown in figure 2.

The results of two types of mechanical property tests show that the multifunctional ionic conduction type high-toughness hydrogel prepared by the method has the maximum tensile strength of 333kPa, the maximum elongation at break of 422% and the maximum compressive strength of 4.22MPa, which indicates that the hydrogel prepared by the method has excellent mechanical properties.

Analytical example 2

The adhesion performance of the SP and CP hydrogel on the surface of the pigskin is measured by using a lap shear test through a universal testing machine, the experimental result is shown in figure 3, and the maximum adhesion strength of the hydrogel prepared by the method on the surface of the pigskin can reach 21.5kPa. Meanwhile, tests show that the prepared hydrogel can be adhered to the surfaces of various materials such as rubber, glass, plastic, metal and the like, and the hydrogel prepared by zwitterions has adhesion universality.

Analytical example 3

The SP hydrogel prepared by the method is cut into rectangular samples with the same size and thickness, a four-probe resistivity tester is used for measuring the resistivity value of the SP hydrogel, and the conductivity of the material is converted, as shown in figure 4, the conductivity of the hydrogel can reach 2.44S/m at most, is improved by two orders of magnitude relative to that of the polyampholyte hydrogel, and the conductivity of the hydrogel shows a trend that the conductivity is firstly improved and then reduced along with the increase of the phytic acid content.

Analytical example 4

The SP hydrogel prepared by the method is cut into rectangular samples with the same size and thickness (50mm 40mm 1.8 mm), and the SP hydrogel is tested in a constant voltage mode by using an electrochemical workstation to obtain the relative resistance change rate (delta R/R) of the hydrogel ₀ ) In relation to its tensile strain. The strain coefficient (GF) is an important parameter for evaluating the sensitivity of a strain sensor and can be defined as the ratio of the relative rate of change of resistance to strain. As shown in FIG. 5, the hydrogel resistance change rate showed a nonlinear monotonic increase in strain, while the strain coefficient GF showed a linear monotonic increase in GF, with GF reaching as high as 9.7.

By combining the mechanical properties and the conductivity performance of the hydrogel, the hydrogel prepared by the method can meet the requirements of preparing flexible and wearable devices.

Analytical example 5

The SP-6 hydrogel which is 0.6mol/L and 1mm in thickness and is prepared by the method is selected. The transmittance spectrum of the hydrogel material was characterized using an ultraviolet-visible spectrophotometer and the transmittance of air was measured at baseline, with the wavelength range selected from 800-400nm.

As shown in FIG. 6, the SP-6 hydrogel had good light transmittance in the visible light range (780-400 nm), and a visible light transmittance of more than 90% was achieved. When the method is applied to health detection, an accurate attachment point can be conveniently found on the tissue and the surface state of the tissue can be observed in real time.

Analytical example 6

The SP hydrogel prepared by the above method was cut into a cylinder shape with a diameter of 10mm and a thickness of 1.8mm with a circular cutter, the hydrogel was placed in an agar plate coated with escherichia coli (e.coli) of the same concentration, cultured in a constant temperature incubator at 37 ℃ for 18 hours, the size of the zone of inhibition was observed and the difference between the zone of inhibition and the diameter of the gel sample was recorded, and the zone of inhibition experiment with staphylococcus aureus (s.aureus) was performed according to this procedure, with the results shown in fig. 7.

The result of the bacteriostatic zone experiment shows that the multifunctional ion conductive high-toughness hydrogel prepared by the method has excellent antibacterial performance on gram-positive bacteria and gram-negative bacteria, and the implantable equipment prepared by the method can effectively reduce the harm of pathogenic microorganisms to human health.

Analytical example 7

The thermal property reaction curve of the hydrogel is measured by using a Differential Scanning Calorimeter (DSC) by sequentially selecting the SP-0, SP-2, SP-4, SP-6, SP-8 and SP-10 hydrogels prepared by the method. Wherein, the crucible test sample is weighed to be about 20mg, and an empty crucible made of the same material is selected as a test reference; the hydrogel is cooled from 30 ℃ to-90 ℃ at a speed of-2 ℃/min.

As shown in figure 8, in the process of cooling at 30 ℃ to-90 ℃, with the increase of the phytic acid content in the system, the strong hydrogen bond effect formed with water is increased, the freezing resistance of the SP hydrogel is gradually improved, and when the phytic acid content in the system reaches 1mol/L (SP-10), no obvious exothermic peak appears in the whole heating process, which indicates that the material has excellent low-temperature freezing resistance.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. An ion-conducting hydrogel, comprising a zwitterionic polymer, phytic acid;

the ionic conduction type hydrogel is of a dual network structure;

2. The ionic conduction type hydrogel according to claim 1, wherein the ionic conduction type hydrogel is composed of a three-dimensional network structure and a continuous aqueous phase;

preferably, there is covalent and electrostatic interaction between the zwitterionic units;

preferably, the zwitterionic polymer forms dipole-dipole interactions and hydrogen bond interactions with the tissue interface;

preferably, the zwitterionic units contain both cationic and anionic charges on the same macromolecular chain;

preferably, the phytic acid dissociates free hydrogen ions under acidic conditions;

preferably, the phytic acid forms ionic and hydrogen bond interactions with the groups of the zwitterionic units;

preferably, the phosphate group in the phytic acid forms a hydrogen bond with a water molecule;

preferably, the zwitterionic monomer is selected from at least one of methacryloyl ethyl sulfobetaine, 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate, 2- ((3-acrylamidopropyl) dimethylammonium) acetate, 2-methacryloyloxyethyl phosphorylcholine;

preferably, the water content in the ionic conduction type hydrogel is 0.36 to 0.61;

preferably, the molar ratio of the zwitterionic polymer in the ionic conduction type hydrogel is 0.67-0.95;

preferably, the molar ratio of the phytic acid in the ion-conductive hydrogel is 0.04 to 0.33.

3. The preparation method of the ionic conduction type hydrogel is characterized by comprising the following steps of:

s2, injecting the gel pre-polymerization liquid into a mold, and carrying out ultraviolet curing or heating to obtain the ionic conduction type hydrogel.

4. The preparation method according to claim 3, wherein in step S1, the rotation speed of stirring is preferably not less than 750r/min;

in the step S1, the concentration of the zwitterionic monomer is 2.0-4.2 mol/L;

preferably, in the step S1, the concentration of the phytic acid is 0.1-1 mol/L;

preferably, in step S1, the initiator includes at least one of a photoinitiator and a thermal initiator;

preferably, in step S1, the photoinitiator is selected from at least one of 2-hydroxy-2-methyl propiophenone, 2-oxoglutaric acid, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-propanone;

preferably, in step S1, the thermal initiator is at least one selected from the group consisting of potassium persulfate, ammonium persulfate, and sodium persulfate.

5. The method according to claim 3, wherein in step S1, the chemical crosslinking agent is at least one selected from the group consisting of polyethylene glycol diacrylate, N-methylenebisacrylamide, polyethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethyleneoxy polyethylene glycol (meth) acrylate, 6,6 '-diamino-3,3' -methylene dibenzoic acid.

6. The method according to claim 3, wherein the concentration of the initiator is 0.002mol/L to 0.02mol/L;

preferably, in step S1, the concentration of the chemical crosslinking agent is 0.002mol/L to 0.02mol/L.

7. The production method according to claim 3, wherein in step S2, the conditions for UV curing are as follows:

the time is 10min to 45min;

preferably, in step S2, the wavelength of the ultraviolet light is 200nm to 420nm.

8. The production method according to claim 3, wherein in step S2, the heating conditions are as follows:

the temperature is 55-85 ℃;

the time is 18-24 h.

9. The method of claim 3, comprising the steps of:

10. Use of the ionic conduction type hydrogel according to any one of claims 1 to 2 and/or the ionic conduction type hydrogel obtained by the preparation method according to any one of claims 3 to 9 in a flexible wearable device and a wound dressing.