CN113698532B - Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors - Google Patents

Abstract

The invention relates to a preparation method of a multifunctional polymer dicationic hydrogel for a wearable sensor, which comprises the following steps: under the condition of ice-water bath, sequentially adding deionized water, ionic liquid and quaternary ammonium salt into a container, and stirring until a homogeneous solution of 40-300 g/L is formed; then, quickly adding a cross-linking agent and a photoinitiator, and stirring for 10 to 60 min to obtain a monomer mixture containing the initiator; and transferring the monomer mixture containing the initiator into a required mold, and reacting for 6-12 h under illumination to obtain the multifunctional polymer dicationic hydrogel for the wearable sensor. The invention has simple preparation process and good biocompatibility, can directly act on human skin, is safe and reliable, and has potential application value in the aspects of human-computer interaction and intelligent wearable equipment.

Description

Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors

technical field

The invention relates to the field of hydrogel technology and the field of conductive material science, in particular to a multifunctional (excellent mechanical applicability, high sensitivity, antibacterial and antifreeze properties, etc.) polymer dicationic hydrogel for wearable sensors method of preparation.

Background technique

With the development of smart terminals and the continuous improvement of people's quality of life requirements, the development of various sensor technologies and smart devices has made it possible to collect human behavior in real time and conveniently. In order to realize long-term continuous monitoring of human activities, electronic devices with conductive properties need to be installed on the surface of the human body. The main components of traditional electronic devices are hard polymer materials and inorganic semiconductor materials. Due to their brittleness and rigidity, it is difficult to realize wearable devices.

In order to meet the needs of complex human motion, flexible and humanized design has gradually become an important part of wearable electronic devices. Flexible wearable sensors are devices with sensing functions prepared by imitating the characteristics of human skin. In recent years, they have shown great application potential in the fields of artificial intelligence, machine perception, and human-computer interaction. However, most flexible substrates are used as sensor materials. It faces great difficulties in conductivity, which affects its sensitivity and stability as a wearable sensor. Filling conductive materials is the most common method to solve such problems, in which organic conductive polymers (polyaniline, polypyrrole, etc.) are often filled to build a conductive network, good interfacial compatibility can prepare uniform conductive polymer elasticity body, but the inherent color of the filler affects the transparency of the flexible sensor, limiting its application in the field of visual electronics. Flexible materials filled with inorganic conductive particles (graphene, metal nanowires, etc.) have high conductivity, but the phase separation between the filler and the matrix usually reduces its strainability, toughness and fatigue, and even affects the mechanical properties of flexible materials . Therefore, most of the reported wearable sensors are still stuck in the difficult choice of mechanical and electrical conductivity.

Hydrogel is a hydrophilic material with a network structure. A high content of water can provide a transport path for conductive ions, and its satisfactory elasticity and toughness can also be obtained through directional design. Conductive hydrogels can build a conductive network with free ions, and ion conduction can be seen everywhere in biological systems, and they also have excellent biocompatibility, making them a promising candidate for wearable sensors. Therefore, the development of hydrogel-based wearable materials is currently the best choice for human motion detection, health monitoring, and soft robotics.

However, hydrogels using water as a solvent lose their elasticity, ductility, and conductivity at subzero temperatures, resulting in loss of sensing performance, which seriously hinders their practical applications in real life. Therefore, it is necessary to develop hydrogels capable of functioning at subzero temperatures as flexible and wearable sensors. Many antifreeze methods have been designed to achieve this goal, such as the preparation of antifreeze conductive hydrogels by adding ionic compounds or organic solvents. Wang Xiaohui et al. (invention patent CN110760152 A) disclosed an antifreeze hydrogel and its preparation method and application. By adding lithium salt, the hydrogel has antifreeze properties at low temperature, but lithium salt has certain toxicity, and long-term contact is not effective. Beneficial to human health. Yuan Weizhong et al. (invention patent CN112521630 A) disclosed a preparation method and application of a green flexible conductive antifreeze hydrogel. Glycerin is introduced into the hydrogel to improve the antifreeze of the material. However, this method will reduce the mechanical properties. Therefore, hydrogels for wearable sensors must firstly possess excellent mechanical properties and antifreeze properties.

In addition, flexible wearable electronic devices need to be attached to human skin or tissue for a long time, which is easy to cause allergies or bacterial infections. It is also necessary to develop wearable electronic devices that can slow down or prevent microbial reproduction or form biofilms on the surface. Commonly used antibacterial materials are generally combined with antibiotics, antibacterial metal ions or antibacterial peptides to achieve antibacterial purposes. Zhao Xuefeng et al. (invention patent CN 108498543 A) disclosed a silver ion supramolecular antibacterial hydrogel and its preparation method and application. By adding silver ions to guanine derivatives to form a supramolecular hydrogel, silver ion The slow-release and then reached the purpose of antibacterial. Qian Junmin et al. (invention patent CN 112480434 A) disclosed a copper ion antibacterial hydrogel and its preparation method and application. By adding copper salt, the hydrogel is endowed with antibacterial properties, which overcomes the slow release and uncontrollable release rate of copper-containing antibacterial materials. The problem. Chen Gang (invention patent CN 112899331 A) disclosed a fermentation preparation method of antimicrobial peptides, antimicrobial peptide hydrogel and its application, and realized the controlled release of lactic acid based on PEG nanocarriers. However, the widespread use of antibiotics can easily lead to drug resistance of bacteria, the release of metal ions can easily lead to metal poisoning, and the synthesis process of antimicrobial peptides is relatively complicated and can easily cause hemolytic effects. Therefore, wearable sensor hydrogels must also possess broad-spectrum antimicrobial properties.

The development of multifunctional hydrogels with excellent mechanical applicability, high sensitivity, long-lasting antibacterial and antifreeze properties is of great significance for the wide application of wearable sensors. Polyionic liquids (polymers formed from ionic liquids) combine the low volatility, thermal and electrochemical stability of ionic liquids with the mechanical durability of polymers. Because of the charge in the structural unit, it has been widely used in biocompatible materials, anti-fouling, anti-frost coatings and other materials. Antimicrobial polymers have also attracted attention due to their inherent antimicrobial activity that lasts longer than other antimicrobial materials and is less toxic to human cells. Protonated primary amines (quaternary ammonium salts), as cationic antibacterial agents, can interact with negatively charged bacterial membranes through electrostatic attraction, resulting in uneven charge distribution on bacterial cell membranes, thereby breaking the charge balance of cell membranes in a natural state, making them Unable to withstand the osmotic pressure and rupture, substances such as water and protein will seep out of the cell, causing bacterial death. Zhang Cong et al. (invention patent CN107970488 A) disclosed a chitosan quaternary ammonium hydrogel antibacterial dressing and its preparation method. The chitosan quaternary ammonium salt, organosilicon quaternary ammonium salt and dandelion extract were used in combination to experiment. Growth inhibition of Escherichia coli and Staphylococcus aureus. Wang Rongmin et al. (invention patent CN 111217956 A) disclosed a method for preparing cationic custard-shaped acrylate copolymer antibacterial microspheres. The antibacterial microspheres prepared with cationic quaternary ammonium salts as antibacterial units have broad-spectrum antibacterial properties. It can be popularized and applied to the antibacterial and anticorrosion of plant antibacterial, coating, ink and other products. However, there are few studies on the application of quaternary ammonium salts as cationic antibacterial agents in wearable sensors.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a multifunctional polymer dicationic hydrogel for wearable sensors with simple process, good biocompatibility, safety and reliability.

In order to solve the above problems, the preparation method of the multifunctional polymer dicationic hydrogel for wearable sensors according to the present invention is characterized in that: under the condition of ice-water bath, deionized water, ionic liquid, quaternary Ammonium salt, stirred until a homogeneous solution of 40-300 g/L was formed; then quickly added cross-linking agent, photoinitiator, and stirred for 10-60 min to obtain a monomer mixture containing the initiator; the monomer mixture containing the initiator The body mixture was transferred to the required mold, and reacted for 6-12 h under light to obtain the multifunctional polymer dicion hydrogel for wearable sensors.

The temperature of the ice-water bath is -4°C to 0°C.

The mass ratio of the ionic liquid, the quaternary ammonium salt, and the crosslinking agent is 0.20-3.30:1.10-5.50:0.01-0.30.

The ionic liquid refers to 1-butyl-3-vinylimidazole bromide, 1-propyl-3-vinylimidazole sulfonate or 1-ethyl-3-(1-vinylimidazole-3-hexyl ) One of the imidazolium bromide salts.

The quaternary ammonium salt refers to N,N,N-trimethyl-3-(2-methacrylamino)-1-propylammonium chloride or γ-(methacrylamide)propyltrimethylchloride Ammonium.

The crosslinking agent is N,N'-methylenebisacrylamide or ethylene glycol diacrylate.

The photoinitiator is 2-hydroxyl-2-methyl-1-phenylacetone, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester or 2-hydroxyl-4'-(2- The one in hydroxyethoxy)-2-methyl propiophenone, its consumption is 2%～10% of the sum of described ionic liquid and described quaternary ammonium salt quality.

The conditions of the illumination refer to ultraviolet light of 250-400 nm.

Compared with the prior art, the present invention has the following advantages:

1. The present invention uses ionic liquids and quaternary ammonium salts as comonomers to prepare multifunctional polymer dicationic hydrogels for wearable sensors through photo-induced free radical polymerization. The preparation process is simple and the biocompatibility is good. It can directly act on human skin, safe and reliable.

2. The addition of quaternary ammonium salts in the present invention can effectively inhibit the growth of bacteria during long-term wearing, reduce the replacement frequency of sensors, and prolong the service life of wearable sensors.

3. The addition of the ionic liquid in the present invention not only increases the conductivity of the hydrogel, but also endows the dicationic hydrogel with excellent frost resistance, expanding its application in harsh environments.

4. There are a large number of hydrophobic associations and electrostatic interactions inside the multifunctional polymer dicationic hydrogel for wearable sensors prepared by the present invention, which can further enhance the mechanical properties of the hydrogel. At the same time, the dicationic hydrogel can accurately convert different movements of the human body into electrical signals and achieve stable transmission.

5. The multifunctional polymer dicationic hydrogel for wearable sensors prepared by the present invention can be designed into a desired shape through a mold, which is easy to carry and use.

6. The multifunctional polymer dicationic hydrogel for wearable sensors prepared by the present invention has excellent mechanical properties and conductivity sensitivity, and these characteristics determine that the multifunctional polymer dicationic hydrogel for wearable sensors can be sensitive Realize the real-time monitoring of human movement. In addition, the dicationic hydrogel has good antibacterial properties against both Staphylococcus aureus and Escherichia coli, remains transparent and flexible at low temperatures, and can withstand cyclic twisting, bending and folding, these properties make wearable sensors suitable for Multifunctional polymer dicationic hydrogels have comprehensive properties similar to smart skin and have potential applications in human-computer interaction and smart wearable devices.

Description of drawings

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Figure 1 is the macroscopic photo (left picture) and SEM picture (right picture) of the multifunctional polymer dicion hydrogel for wearable sensors prepared in Example 1 of the present invention.

Fig. 2 is the infrared spectrum of the multifunctional polymer dicationic hydrogel for wearable sensors prepared in Example 1 of the present invention.

Fig. 3 is the NMR spectrum of the multifunctional polymer dicion hydrogel for wearable sensors prepared in Example 1 of the present invention.

Fig. 4 is a graph showing the mechanical properties of the multifunctional polymer dicative hydrogel for wearable sensors prepared in Example 1 of the present invention.

Fig. 5 is a test diagram of the electrical conductivity of the multifunctional polymer dicationic hydrogel for wearable sensors prepared in Example 1 of the present invention.

Fig. 6 is a graph showing the frost resistance test of the multifunctional polymer dication hydrogel for wearable sensors prepared in Example 1 of the present invention.

Fig. 7 is a comparison diagram of the antibacterial effect of the multifunctional polymer dicationic hydrogel for wearable sensors prepared in Example 1 of the present invention. Among them: a is Staphylococcus aureus (control); b is Staphylococcus aureus (48 h); c is Escherichia coli (control); d is Escherichia coli (48 h).

Fig. 8 is an action monitoring diagram of the multifunctional polymer dicationic hydrogel for wearable sensors prepared in Example 1 of the present invention.

Detailed ways

The preparation method of multifunctional polymer dicationic hydrogel for wearable sensors: Add deionized water, ionic liquid, and quaternary ammonium salt to the container in sequence under the condition of -4°C~0°C ice-water bath, and stir until 40~ 300 g/L homogeneous solution; then quickly add crosslinking agent and photoinitiator, stir for 10-60 min to obtain monomer mixture containing initiator; transfer the monomer mixture containing initiator to the required mold, and use The ultraviolet light of 250-400 nm was reacted under light for 6-12 h to obtain a multifunctional polymer dicationic hydrogel for wearable sensors.

Among them: the mass ratio (g/g) of ionic liquid, quaternary ammonium salt and crosslinking agent is 0.20~3.30:1.10~5.50:0.01~0.30.

Ionic liquid refers to 1-butyl-3-vinylimidazolium bromide, 1-propyl-3-vinylimidazole sulfonate or 1-ethyl-3-(1-vinylimidazol-3-hexyl)imidazole One of the bromine salts.

The quaternary ammonium salt refers to N,N,N-trimethyl-3-(2-methacrylamide)-1-propylammonium chloride or γ-(methacrylamide)propyltrimethylammonium chloride.

The crosslinking agent is N,N'-methylenebisacrylamide or ethylene glycol diacrylate.

The photoinitiator is 2-hydroxy-2-methyl-1-phenylacetone, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester or 2-hydroxy-4′-(2-hydroxyethyl Oxygen)-2-methyl propiophenone, its consumption is 2%～10% of the sum of described ionic liquid and described quaternary ammonium salt quality.

Example 1 Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors: Add deionized water, 2.16 g 1-butyl-3- Vinylimidazolium bromide, 2.21 g N,N,N-trimethyl-3-(2-methacrylamino)-1-propylammonium chloride, stirred until a homogeneous solution of 200 g/L was formed; then Add 0.02 g N,N′-methylenebisacrylamide and 0.11 g 2-hydroxy-2-methyl-1-phenylacetone rapidly, and stir for 20 min to obtain a monomer mixture containing an initiator; The body mixture was transferred to the desired mold, and reacted under 254nm ultraviolet light for 9 h to obtain a multifunctional polymer dicationic hydrogel for wearable sensors.

Structural characterization and performance analysis of the prepared multifunctional polymer dicationic hydrogel for wearable sensors:

⑴ Scanning electron microscope analysis:

The macroscopic morphology (left image) and microscopic morphology (right image) of the multifunctional polymer dicationic hydrogel for wearable sensors prepared by the present invention were observed with a digital camera and a scanning electron microscope (SEM). The results are shown in Figure 1 shown. It can be seen that the multifunctional polymer dicationic hydrogel for wearable sensors has good plasticity, smooth and flexible surface, and can be easily designed into the desired shape through the mold according to the demand.

From the SEM photos, it can be seen that the material shows a typical porous structure, and the pore size is relatively uniform, about 8 µm. This structure can disperse external forces from all sides, and can improve the material's dispersion of tensile and extrusion forces. , and the porous structure is also conducive to the migration of ions. In addition, the porous structure is also conducive to increasing the contact area between the hydrogel and bacteria, which has a positive effect on improving its antibacterial performance.

⑵Infrared spectrum analysis:

The infrared spectrum of the multifunctional polymer dication hydrogel for wearable sensors is shown in Fig. 2. It can be seen from the figure that the absorption peak at 3438 cm ^-1 is the stretching vibration of -NH; the peaks around 3032 cm ^-1 and 2956 cm ^-1 are the unsaturated saturation stretching vibration absorption peaks of CH; the carbonyl ( The stretching vibration absorption peak of C=O) is located at 1645 cm ^-1 ; the bending vibration characteristic absorption peak of -CH ₂ -N ⁺ (CH ₃ ) ₃ methylene is at 1484 cm ^-1 . In addition, the absorption peak at 3138 cm ^-1 is caused by the stretching vibration of CH in imidazole, and the absorption peaks at 1568 cm ^-1 and 1456 cm ^-1 are attributed to the skeleton vibration of imidazole. This proves that all monomers participate in the reaction, and the multifunctional polymer dicationic hydrogel for wearable sensors has been successfully prepared.

⑶ NMR spectrum analysis:

The solid-state carbon NMR spectrum of the multifunctional polymer dicationic hydrogel for wearable sensors is shown in Figure 3. The characteristic peaks at 176.70 ppm and 161.06 ppm belong to the proton chemical shift of the carbonyl group; the characteristic resonance peaks of the imidazole ring appear at 137.36 ppm and 123.33 ppm; the characteristic peak at 53.83 ppm is the proton chemical shift of the terminal methyl group of the quaternary ammonium salt. It can be proved that all the monomers participated in the polymerization reaction, which further proves that the multifunctional polymer dicationic hydrogel was successfully prepared for wearable sensors.

⑷Mechanical properties:

The tensile properties of the multifunctional polymer dication hydrogels for wearable sensors were tested on a universal testing machine.

First, the sample was cut into rectangular slices (length = 50 mm, width = 10 mm, thickness = 2 mm), and the uniaxial tensile rate was set at 50 mm/min. Secondly, fix the cut gel rectangular slices on the upper and lower clamps of the universal testing machine, and tighten the clamps. Pay attention to the strength of the screw clamps and the length of the two ends of the gel clamped into the clamps to prevent the gel from being crushed. Glue or slip out during stretching. The uniaxial tensile test cannot be interrupted halfway until the gel breaks. The test results shown in Figure 4 are the stress-strain curves of the multifunctional polymer dicationic hydrogel for wearable sensors.

It can be seen from the figure that the multifunctional polymer dicationic hydrogel for wearable sensors has excellent mechanical properties, the maximum strain exceeds 500%, and the stress can reach 900 kPa, which can fully meet the elasticity of flexible wearable sensors (0.4~1.9 MPa) and flexibility (elongation greater than 180%) requirements.

⑸Function test:

①Conductive properties:

The conductivity of the wearable sensor was verified by connecting the wearable sensor with a multifunctional polymer dicationic hydrogel as a wire with an LED bulb and a 3 V external power supply to form a complete circuit. Test process: The LED bulb is lit when the double cation hydrogel is connected to the circuit (Figure 5a), which is due to the good conductivity of the double cation hydrogel. Cutting through the dicationic hydrogel breaks the circuit and the LED bulb turns off (Fig. 5b). This demonstrates the excellent electrical stability and sensitivity of the multifunctional polymer dicationic hydrogel for wearable sensors, and thus can be used as a wearable sensor for human motion monitoring.

② Antifreeze performance:

After freezing at -10°C for 24 h with multifunctional polymeric cation hydrogels for wearable sensors, it still maintained transparency and flexibility. Further stretching experiments revealed that the multifunctional polymeric dianionic hydrogels could still be Stretch to twice its original length (Figure 6). It shows that the addition of ionic liquids makes the multifunctional polymer dicationic hydrogels for wearable sensors have good freezing resistance, which expands the application range of hydrogels as flexible wearable materials.

③Antibacterial properties:

Test process: Staphylococcus aureus and Escherichia coli were used as representatives of Gram-positive and Gram-negative bacteria, respectively, and the antibacterial properties of multifunctional polymer dicationic hydrogels for wearable sensors were tested by plate counting . First, the material is cut into discs, and the discs to be tested are sterilized before the antibacterial experiment. Secondly, the sterilized material disk and the activated bacterial suspension were added to phosphate buffered saline (PBS buffer) as the experimental group; the PBS buffer containing bacteria was used as the control group. The samples of the experimental group and the control group were incubated in a constant temperature shaker at 37°C for 4 h. Finally, the obtained bacterial suspension was spread on a nutrient agar plate and incubated in a constant temperature incubator at 37°C for 48 h to observe the growth of the colonies. The experimental results are shown in Figure 7.

The survival of bacterial colonies can be clearly seen from the antibacterial photos of the culture plate (the small white spots growing on the plate represent surviving bacterial colonies). On the control plate, both S. aureus (a) and E. coli (c) showed relatively dense colonies, indicating that S. Unlimited growth. The growth of Staphylococcus aureus (b) and Escherichia coli (d) colonies on the culture plate was significantly restricted after the bacterial suspension was in contact with the multifunctional polymer dicationic hydrogel for a period of time, which indicated that the wearable sensor could be used The multifunctional polymer dicationic hydrogel exhibited good antibacterial activity against both Staphylococcus aureus and Escherichia coli.

The results showed that the material showed remarkable antibacterial properties against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), and had a broad-spectrum antibacterial activity, which overcomes the long-term The disadvantages of allergies and bacterial infections easily caused by attachment to human skin or tissues.

④ Action monitoring:

The wearable sensor is attached to various parts of the human body with multifunctional polymer dication hydrogel, and its two ends are connected to the digital source meter through copper wires, and the multifunctional polymer dication water gel used for the wearable sensor is recorded through the digital source meter. The resistance of the gel varies with strain to obtain a resistance-strain curve, and accurate monitoring of human body movements can be realized through changes in the shape and strength of the resistance-strain curve.

Figure 8 shows the relative resistance (ΔR/R ₀ ) change of the multifunctional polymer dicative hydrogel for wearable sensors during human motion. It can be seen from the figure that when the human joints start to move, the change of the relative resistance of the multifunctional polymer dicationic hydrogel begins to increase, and reaches the maximum value when the joint movement range is the largest. The relative resistance change of the bication hydrogel begins to decrease, and the same action can be repeated continuously, and the signal can be continuously and repeatedly output, thus verifying the high strain sensitivity and fast action of the multifunctional polymer bication hydrogel for wearable sensors. Responsive and repeatable.

Example 2 Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors: Add deionized water, 2.54 g 1-propyl-3- Vinylimidazole sulfonate, 3.56 g N,N,N-trimethyl-3-(2-methacrylamido)-1-propylammonium chloride, stirred until a homogeneous solution of 250 g/L was formed; Then, 0.22 g of N,N′-methylenebisacrylamide and 0.32 g of ethyl 2,4,6-trimethylbenzoylphenylphosphonate were added rapidly, and stirred for 30 min to obtain a monomer mixture containing the initiator ; The monomer mixture containing the initiator was transferred to a mold with 254 nm ultraviolet light and reacted for 6 h to obtain a multifunctional polymer dicationic hydrogel for wearable sensors.

Example 3 Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors: Add deionized water, 1.32 g 1-ethyl-3- (1-vinylimidazol-3-hexyl) imidazolium bromide, 4.05 g γ-(methacrylamide) propyltrimethylammonium chloride, stirred until a homogeneous solution of 115 g/L was formed; then quickly added 0.15 g ethyl alcohol Diol diacrylate, 0.17 g 2-hydroxyl-4'-(2-hydroxyethoxy)-2-methylpropiophenone, stirred for 25 min to obtain a monomer mixture containing the initiator; the monomer containing the initiator The mixture was transferred to the desired mold, and reacted with 365 nm ultraviolet light for 10 h under light to obtain a multifunctional polymer dicationic hydrogel for wearable sensors.

Example 4 Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors: Add deionized water, 0.98 g 1-butyl-3- Vinylimidazolium bromide, 1.89 g γ-(methacrylamide) propyltrimethylammonium chloride, stirred until a homogeneous solution of 180 g/L was formed; then quickly added 0.18 g ethylene glycol diacrylate, 0.33 g 2- Hydroxy-2-methyl-1-phenylacetone was stirred for 50 min to obtain a monomer mixture containing an initiator; the monomer mixture containing an initiator was transferred to the required mold and reacted under ultraviolet light at 254 nm for 10 h, The obtained multifunctional polymer dicationic hydrogel for wearable sensors.

Example 5 Preparation method of multifunctional polymer dicationic hydrogel for wearable sensors: Add deionized water, 3.01 g 1-ethyl-3- (1-vinylimidazol-3-hexyl)imidazolium bromide, 2.88 g N,N,N-trimethyl-3-(2-methacrylamido)-1-propylammonium chloride, stirred until 70 g/L homogeneous solution; then quickly added 0.29 g N,N′-methylenebisacrylamide, 0.55 g 2-hydroxy-2-methyl-1-phenylacetone, stirred for 40 min, and obtained The monomer mixture containing the initiator; the monomer mixture containing the initiator was transferred to the required mold, and reacted under 365 nm ultraviolet light for 12 h to obtain a multifunctional polymer dicationic hydrogel for wearable sensors.

Claims (5)

1. The preparation method of the multifunctional polymer dicationic hydrogel for the wearable sensor is characterized by comprising the following steps: under the condition of ice-water bath, sequentially adding deionized water, ionic liquid and quaternary ammonium salt into a container, and stirring until a homogeneous solution of 40-300 g/L is formed; then, quickly adding a cross-linking agent and a photoinitiator, and stirring for 10 to 60 min to obtain a monomer mixture containing the initiator; transferring the monomer mixture containing the initiator into a required mold, and reacting for 6 to 12 hours under illumination to obtain the multifunctional polymer dicationic hydrogel for the wearable sensor; the ionic liquid is one of 1-butyl-3-vinyl imidazole bromide, 1-propyl-3-vinyl imidazole sulfonate or 1-ethyl-3- (1-vinyl imidazole-3-hexyl) imidazole bromide; the quaternary ammonium salt is N, N, N-trimethyl-3- (2-methallylamido) -1-propyl ammonium chloride or gamma- (methacrylamide) propyl trimethyl ammonium chloride; the cross-linking agent is N, N' -methylene bisacrylamide or ethylene glycol diacrylate.

2. The method for preparing the multifunctional polymer dicationic hydrogel for the wearable sensor according to claim 1, wherein: the temperature of the ice-water bath is-4 ℃ to 0 ℃.

3. The method for preparing the multifunctional polymer dicationic hydrogel for the wearable sensor according to claim 1, wherein: the mass ratio of the ionic liquid to the quaternary ammonium salt to the cross-linking agent is 0.20 to 3.30:1.10 to 5.50:0.01 to 0.30.

4. The method for preparing the multifunctional polymer dicationic hydrogel for the wearable sensor according to claim 1, wherein: the photoinitiator is one of 2-hydroxy-2-methyl-1-phenyl acetone, 2,4, 6-trimethyl benzoyl phenyl ethyl phosphonate or 2-hydroxy-4' - (2-hydroxyethoxy) -2-methyl propiophenone, and the usage amount of the photoinitiator is 2% -10% of the sum of the mass of the ionic liquid and the mass of the quaternary ammonium salt.

5. The method for preparing the multifunctional polymer dicationic hydrogel for the wearable sensor according to claim 1, wherein: the illumination condition is that ultraviolet light of 250 to 400 nm is adopted.

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