Quaternary ammonium salt containing carbamate structure as well as preparation method and application of quaternary ammonium salt

Abstract

The invention belongs to the technical field of hydrogel sensors, and particularly relates to quaternary ammonium salt containing a carbamate structure as well as a preparation method and application of the quaternary ammonium salt. The structural formula of the quaternary ammonium salt is # imgabs0 #; wherein n comprises an integer from 7 to 17; m comprises an integer of 2-4; x comprises Cl, Br, I and F; the quaternary ammonium salt contains a carbamate group and can form a hydrogen bond, so that the quaternary ammonium salt and the generated hydrogel have excellent hydrophilicity and water-retaining property; the hydrogel participating in preparation has excellent fatigue resistance, tensile hysteresis, biocompatibility and antibacterial property.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogel sensors, and particularly relates to a quaternary ammonium salt containing a carbamate structure, a preparation method thereof, and an application thereof. Background Art

[0002] Traditional sensor materials have obvious deficiencies in antibacterial performance and mechanical strength. Especially in humid or biological environments, the defects in strength and stability of conventional hydrogel sensor materials often limit the lifespan and reliability in practical applications. Existing hydrogels still need to be improved in terms of antibacterial effect, response speed, and adaptability to the application environment. Therefore, the research and development of antibacterial hydrogels have become one of the important directions in materials science.

[0003] Antibacterial hydrogel sensors combine the biocompatibility and flexibility of hydrogel materials, and at the same time incorporate antibacterial components to meet safety requirements. Currently, most research focuses on introducing antibacterial agents through physical or chemical doping methods to enhance antibacterial performance, such as adding silver ions, antibacterial peptides. However, some antibacterial additives may cause biocompatibility problems. Especially in medical and biosensing applications, improper use of antibacterial agents may lead to local toxic reactions, limiting the feasibility of their practical applications.

[0004] There are also ways to use quaternary ammonium salts as the backbone to achieve antibacterial performance. However, the long hydrophobic chain will reduce the water solubility of the quaternary ammonium salt monomer, affect its addition amount in the hydrogel, and there is a problem of limited addition amount. The too-long hydrophobic chain may also reduce the interaction between the hydrophilic networks inside the hydrogel, resulting in a decrease in antibacterial performance and mechanical properties. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of poor biocompatibility of existing hydrogels containing antibacterial agents, insufficient antibacterial performance and mechanical properties of hydrogels containing quaternary ammonium salt groups, and limited addition amount of quaternary ammonium salts due to too-long chain segments, so as to provide a quaternary ammonium salt containing a carbamate structure, a preparation method thereof, and an application thereof.

[0006] For this purpose, the present invention provides the following technical solutions: The first aspect of the present invention protects a quaternary ammonium salt containing a carbamate structure, wherein the structural formula of the quaternary ammonium salt is: ; wherein, n includes an integer from 7 to 17; m includes an integer from 2 to 4; X includes Cl, Br, I, F.

[0007] The second aspect of the present invention protects a preparation method of the aforementioned quaternary ammonium salt containing a carbamate structure, which includes the following steps: S1. Mix N,N-dimethylaminoalkyl alcohol, haloalkane, and solvent A to conduct the first reaction, followed by solid-liquid separation to obtain a quaternary ammonium salt intermediate. S2. Mix the quaternary ammonium salt intermediate, isocyanatoethyl methacrylate, inhibitor, catalyst, and solvent B to conduct the second reaction, followed by solid-liquid separation to obtain a quaternary ammonium salt containing a carbamate structure.

[0008] In the present invention, taking N,N-dimethylethanolamine and 1-chlorooctane as examples, the specific reaction chemical formulas are as follows: First is the S1 reaction. ; The S1 reaction is the synthesis of the quaternary ammonium salt intermediate, which undergoes nucleophilic substitution through the SN2 mechanism. In this reaction, the nitrogen atom with a lone pair of electrons in the N,N-dimethylethanolamine molecule acts as a nucleophile, attacking the primary carbon atom with a partial positive charge in the chloroalkane. Meanwhile, the chloride ion leaves as a leaving group, and finally, the quaternary ammonium salt intermediate is formed. Next is the S2 reaction. ; The S2 reaction is a nucleophilic addition process between an isocyanate group and an alcohol hydroxyl group: that is, the hydroxyl group (-OH) in the quaternary ammonium salt molecule acts as a nucleophile, attacking the central carbon atom of the isocyanate group (-N=C=O) in the isocyanatoethyl methacrylate molecule to form a carbamate group (-NH-COO-), and finally, a quaternary ammonium salt containing a carbamate structure is obtained.

[0009] In the present invention, after the first reaction, it is cooled to room temperature and then post-treated; after the second reaction, it is cooled to room temperature and then solid-liquid separation is carried out. Typically and non-limitingly, the solid-liquid separation is carried out by evaporating the solvent.

[0010] According to the present invention, the N,N-dimethylaminoalkyl alcohol includes at least one of N,N-dimethylethanolamine, N,N-dimethylpropanolamine, and N,N-dimethylbutanolamine.

[0011] According to the present invention, the haloalkane includes at least one of chloroalkane, bromoalkane, iodoalkane, and fluoroalkane.

[0012] According to the present invention, the chloroalkane includes at least one of 1-chlorooctane, 1-chlorononane, 1-chlorodecane, 1-chloroundecane, 1-chlorododecane, 1-chlorotridecane, 1-chlorotetradecane, 1-chloropentadecane, 1-chlorohexadecane, 1-chloroheptadecane, and 1-chlorooctadecane.

[0013] According to the present invention, the bromoalkane includes at least one of 1-bromooctane, 1-bromononane, 1-bromodecane, 1-bromoundecane, 1-bromododecane, 1-bromotridecane, 1-bromotetradecane, 1-bromopentadecane, 1-bromohexadecane, 1-bromoheptadecane, and 1-bromooctadecane.

[0014] According to the present invention, the iodoalkane includes at least one of 1-iodooctane, 1-iodononane, 1-iododecane, 1-iodoundecane, 1-iodododecane, 1-iodotridecane, 1-iodotetradecane, 1-iodopentadecane, 1-iodohexadecane, 1-iodoheptadecane, and 1-iodooctadecane.

[0015] According to the present invention, the fluoroalkane includes at least one of 1-fluorooctane, 1-fluorononane, 1-fluorodecane, 1-fluoroundecane, 1-fluorododecane, 1-fluorotridecane, 1-fluorotetradecane, 1-fluoropentadecane, 1-fluorohexadecane, 1-fluoroheptadecane, and 1-fluorooctadecane.

[0016] According to the present invention, the solvent A and the solvent B each independently include at least one of ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, and N,N-dimethylformamide.

[0017] According to the present invention, in step S1, the dosage ratio of the haloalkane to the solvent A is 1 mmol:(2 - 3) mL.

[0018] According to the present invention, in step S2, the dosage ratio of the quaternary ammonium salt intermediate to the solvent B is 1 mmol:(2 - 3) mL.

[0019] In the present invention, actually, the N,N-dimethylaminoalkyl alcohol reacts with the haloalkane in a molar ratio of 1:1. To ensure the smooth progress of the reaction, the haloalkane is slightly in excess. When adding, generally, the N,N-dimethylaminoalkyl alcohol and the haloalkane are added in a molar ratio of 1:1 - 1.05.

[0020] According to the present invention, the temperature of the first reaction is 45 - 60 °C and the time is 6 - 12 h.

[0021] In step S1 of the present invention, the product after the first reaction is collected for solid-liquid separation, and an ether reagent is also used to wash the separated solid to remove impurities, and the quaternary ammonium salt intermediate is obtained after drying; the ether reagent is a conventional reagent in the art. Typically and non-limitingly, the ether reagent includes diethyl ether and / or methyl ethyl ether; the solid-liquid separation is carried out by filtration; the ether reagent is used to wash away the unreacted substances.

[0022] According to the present invention, the inhibitor comprises at least one of phenolic compounds or quinone compounds; optionally, the inhibitor comprises at least one of hydroquinone, p-methoxyphenol, p-benzoquinone, and methylhydroquinone; further optionally, the inhibitor comprises p-methoxyphenol.

[0023] In the present invention, actually, the quaternary ammonium salt intermediate reacts with isocyanatoethyl methacrylate in a molar ratio of 1:1. However, to facilitate the reaction, a slightly excessive amount of the quaternary ammonium salt intermediate is added.

[0024] According to the present invention, based on the molar amount of isocyanatoethyl methacrylate, the dosage of the inhibitor is 0.1 - 0.3 mol%.

[0025] According to the present invention, the catalyst comprises an organotin salt; optionally, the catalyst comprises at least one of dibutyltin dilaurate and stannous octoate; further optionally, the catalyst comprises dibutyltin dilaurate.

[0026] According to the present invention, the dosage ratio of isocyanatoethyl methacrylate to the catalyst is 1 mmol : (0.5 - 1) μL.

[0027] According to the present invention, the temperature of the second reaction is 45 - 55 °C and the time is 9 - 12 h.

[0028] In the present invention, the mixing in step S1 and the mixing in step S2 are conventional mixings in the art and can be mixed evenly.

[0029] The third aspect of the present invention protects a preparation method of a quaternary ammonium salt hydrogel containing a carbamate structure, which includes the following steps: mixing a quaternary ammonium salt monomer, an amide group-containing monomer, an initiator, a crosslinking agent, an emulsifier, an inorganic salt, and water to obtain a mixed solution, and performing a polymerization reaction to obtain a quaternary ammonium salt hydrogel containing a carbamate structure; Among them, the quaternary ammonium salt monomer is the aforementioned quaternary ammonium salt containing a carbamate structure or the quaternary ammonium salt containing a carbamate structure prepared by the aforementioned preparation method.

[0030] In the present invention, a quaternary ammonium salt containing a carbamate structure prepared from N,N-dimethylethanolamine and 1-chlorooctane and acrylamide are used as reactants, and the specific reaction chemical formula is as follows: ; is the chain segment stretching direction, is the connection site, and the hydrogel preparation is a free radical micelle copolymerization reaction; among them, the emulsifier forms micelles in water as the solubilization site for the quaternary ammonium salt monomer, and the inorganic salt improves the solubilization effect of the micelles; while the amide group-containing monomer and the initiator can undergo free radical polymerization when dissolved in the aqueous solution.

[0031] Among them, the free radical polymerization reaction mainly proceeds in three stages: (1) Under heating conditions, the initiator decomposes to generate free radicals, and the free radicals attack the -C=C- double bond in the amide group-containing monomer to form new free radicals, thereby initiating the polymerization of the amide group-containing monomer and generating active macromolecules with free radical chain ends; (2) When the active macromolecule chain with a free radical chain end encounters a micelle solubilizing a quaternary ammonium salt monomer, it will enter the interior of the micelle and then initiate the polymerization with the quaternary ammonium salt monomer; since multiple quaternary ammonium salt monomers can be solubilized in each micelle, the long carbon chains of these quaternary ammonium salt monomers will spontaneously entangle to gradually form a hydrophobic association microregion; (3) When the monomers in a micelle react completely, the active macromolecule chain with a free radical chain end leaves the micelle and continues to initiate the polymerization of the amide group-containing monomer in the aqueous phase until it encounters the next solubilized micelle. During the polymerization process, when the active macromolecule chain encounters a crosslinking agent, it will attack the -C=C- double bond in the crosslinking agent to form a chemical crosslinking network. The termination of the polymerization reaction may be completed through free radical coupling, chain termination, chain transfer, etc., and finally a crosslinked copolymer is formed.

[0032] In the present invention, after mixing the quaternary ammonium salt monomer, the amide group-containing monomer, the initiator, the crosslinking agent, the emulsifier, the inorganic salt and water, it further includes the steps of introducing nitrogen into the system and ultrasonically removing bubbles to avoid the presence of bubbles in the hydrogel after polymerization, which affects its mechanical properties.

[0033] According to the present invention, the amide group-containing monomer includes at least one of acrylamide, methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-vinyl-N-methylacetamide, N-ethylacrylamide, N,N-dimethylmethacrylamide; optionally, the amide group-containing monomer includes acrylamide.

[0034] According to the present invention, the molar ratio of the quaternary ammonium salt monomer to the amide group-containing monomer is 1:3 - 19; optionally, the molar ratio of the quaternary ammonium salt monomer to the amide group-containing monomer is 1:5 - 10.

[0035] According to the present invention, the initiator includes persulfate; optionally, the initiator includes at least one of ammonium persulfate and potassium persulfate; further optionally, the initiator includes potassium persulfate.

[0036] According to the present invention, based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer, the dosage of the initiator is 0.05 - 0.1 mol%.

[0037] In the present invention, the crosslinking agent includes methylene bisacrylamide; methylene bisacrylamide is a common crosslinking agent for preparing hydrogels. Although it is slightly soluble in solution, due to its small dosage, a small amount of addition can also achieve the crosslinking effect.

[0038] According to the present invention, based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer, the dosage of the crosslinking agent is 0.03 - 0.2 mol%.

[0039] According to the present invention, the emulsifier includes sulfonate; optionally, the emulsifier includes at least one of sodium dodecyl sulfonate and sodium dodecyl benzene sulfonate; further optionally, the emulsifier includes sodium dodecyl sulfonate.

[0040] According to the present invention, based on the mass of the mixed solution, the concentration of the emulsifier is 60 - 100 g / L; optionally, the concentration of the emulsifier is 80 - 90 g / L.

[0041] According to the present invention, the inorganic salt includes chloride and / or bromide; optionally, the inorganic salt includes at least one of lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, and potassium bromide; further optionally, the inorganic salt includes at least one of sodium chloride and lithium chloride.

[0042] According to the present invention, based on the mass of the mixed solution, the concentration of metal ions such as lithium ions, sodium ions, potassium ions, etc. in the inorganic salt is 1 - 3 mol / L, and can be 2 - 2.5 mol / L.

[0043] According to the present invention, the ratio of the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer to the amount of water used is (1.50 - 3.00) mmol:1 mL.

[0044] According to the present invention, the temperature of the polymerization reaction is 35 - 50 °C, and the time is 8 - 12 h.

[0045] The fourth aspect of the present invention protects a quaternary ammonium salt hydrogel containing a carbamate structure prepared by the foregoing preparation method.

[0046] The fifth aspect of the present invention protects an antibacterial material, wherein the antibacterial material includes the foregoing quaternary ammonium salt hydrogel containing a carbamate structure.

[0047] According to the present invention, the antibacterial material is applied in a sensor.

[0048] The technical solution of the present invention has the following advantages: 1. The present invention provides a quaternary ammonium salt containing a carbamate structure, wherein the structural formula of the quaternary ammonium salt monomer is: ; Among them, n includes integers from 7 to 17; m includes integers from 2 to 4; X includes Cl, Br, I, F; the specific structure of the quaternary ammonium salt of the present invention has good hydrophilicity, can be successfully prepared into a hydrogel, and there is no defect of limited addition amount; the presence of double bonds can endow the quaternary ammonium salt monomer with polymerization activity, and introduce the quaternary ammonium salt structure and the carbamate structure into the hydrogel; the quaternary ammonium salt monomer contains a carbamate group (-RNHCOOR'-), and the carbamate group has strong polarity. When prepared into a hydrogel, strong intramolecular and intermolecular hydrogen bonds are formed with groups such as amino and carbonyl groups in the hydrogel, significantly improving the mechanical properties of the prepared hydrogel; at the same time, the carbamate group can also form hydrogen bonds with water molecules, enhancing the hydrophilicity and water retention capacity of the quaternary ammonium salt and the hydrogel prepared therefrom. The rich dynamic hydrogen bonds also help to improve the anti-fatigue property and tensile hysteresis of the hydrogel, thereby improving its sensitivity and sensing stability as a sensor; in addition, due to the good biocompatibility and degradability of the carbamate, the hydrogel can be endowed with excellent biocompatibility; the quaternary ammonium salt group can effectively adsorb negatively charged bacteria through electrostatic attraction, hydrogen bond interaction and hydrophobic interaction between surfactant and protein, ultimately leading to their death, thereby endowing the hydrogel with excellent antibacterial properties.

[0049] 2. The present invention provides a preparation method of a quaternary ammonium salt containing a carbamate structure. First, N,N-dimethylaminoalkyl alcohol, haloalkane, and solvent A are mixed for a first reaction, and solid-liquid separation is carried out to obtain a quaternary ammonium salt intermediate. Among them, the amine group of N,N-dimethylaminoalkyl alcohol undergoes a nucleophilic reaction with the haloalkane to generate a quaternary ammonium salt intermediate; then, the quaternary ammonium salt intermediate, isocyanatoethyl methacrylate, inhibitor, catalyst, and solvent B are mixed for a second reaction. In the second reaction, the hydroxyl group of the quaternary ammonium salt intermediate reacts with the isocyanate group in isocyanatoethyl methacrylate to generate a structure containing a carbamate group (-RNHCOOR') and still retaining a double bond group capable of continuing to react; the stepwise reaction can effectively avoid side reactions and make the reactants have higher reaction activity.

[0050] 3. The specific molar ratio of the quaternary ammonium salt monomer and the amide group-containing monomer in the present invention can further improve the antibacterial performance and mechanical properties of the hydrogel and achieve the balance of various properties. By optimizing the ratio of the quaternary ammonium salt monomer, the antibacterial effect of the hydrogel is enhanced, which is applicable to medical, sanitary and other fields. The reasonable molar ratio design improves the strength of the hydrogel. By achieving the balance of antibacterial performance and mechanical properties, higher use efficiency and a wider application range are brought.

[0051] 4. There are multiple interactions among the quaternary ammonium salt hydrogels containing urethane structures prepared by the present invention. The urethane structure can form intramolecular and intermolecular multiple network hydrogen bonds, endowing the hydrogel with good anti-fatigue performance; while the intramolecular chemical crosslinking can provide basic mechanical strength; the long hydrophobic chains of the quaternary ammonium salt monomers and the emulsifier construct the hydrophobic association network of the hydrogel. The dynamic characteristics of the hydrophobic association network can significantly enhance the mechanical strength and anti-fatigue performance of the hydrogel; the inorganic salts used in constructing the hydrophobic association network exist in the hydrogel network in ionic form, which can act as carriers, endowing the hydrogel with good electrical conductivity. At the same time, there are hydrophobic association microdomains, which can enhance the mechanical strength and anti-fatigue performance of the hydrogel; the urethane structure can improve the water solubility of the quaternary ammonium salt monomers, thereby increasing the addition amount of the quaternary ammonium salt monomers and further enhancing the antibacterial performance of the hydrogel. The synergistic effect of the urethane structure and the quaternary ammonium salt group makes the hydrogel show significant advantages in anti-fatigue and antibacterial properties, and expands the application scope of the hydrogel of the present invention in the field of conductive hydrogel sensors. Description of the Drawings

[0052] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0053] Figure 1 It is the infrared spectrum diagram of the quaternary ammonium salt intermediate-1, the quaternary ammonium salt monomer MQ-1 and the quaternary ammonium salt hydrogel HMQ-1 with urethane structure prepared in Example 1 of the present invention; Figure 2 It is the nuclear magnetic test spectrum diagram of the quaternary ammonium salt monomer prepared in Example 1 of the present invention; Figure 3 It is the scanning electron microscope image of the quaternary ammonium salt hydrogel with urethane structure prepared in Example 1 of the present invention; Figure 4 It is the biocompatibility test result of the quaternary ammonium salt hydrogels with urethane structure prepared in Examples 1-4 and Comparative Example 1 of the present invention; Figure 5 It is the self-recovery performance test result of the quaternary ammonium salt hydrogels with urethane structure prepared in Examples 1-6 and Comparative Example 1 of the present invention, where Figure 5 in (Ⅰ) is the overall test result diagram, Figure 5 in (Ⅱ) is Figure 5 the enlarged view of the test results of Examples 1-6 in (Ⅰ) above; Figure 6This is the comparative test result of the water retention performance of the quaternary ammonium salt hydrogel with a carbamate structure prepared in Examples 1-6 and Comparative Example 1 of the present invention, where Figure 6 in (Ⅰ) is the overall test result diagram, Figure 6 in (Ⅱ) is Figure 6 the enlarged view of the test results of Examples 1-6 in (Ⅰ) therein; Figure 7 This is the test result of the electrical conductivity of the quaternary ammonium salt hydrogel with a carbamate structure prepared in Example 2 of the present invention; Figure 8 This is the test result of the stability of the quaternary ammonium salt hydrogel with a carbamate structure prepared in Example 2 of the present invention when applied as a flexible strain sensor; Figure 9 This is the test result of the electrical conductivity of the quaternary ammonium salt hydrogel with a carbamate structure prepared in Example 2 of the present invention when applied as a motion monitoring sensor. Detailed implementation manners

[0054] The following examples are provided to better further understand the present invention. They are not limited to the best implementation manner, and do not constitute a limitation on the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other existing technologies falls within the protection scope of the present invention.

[0055] For those not specifying specific experimental steps or conditions in the examples, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments not specifying the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0056] Example 1 This example provides a quaternary ammonium salt hydrogel with a carbamate structure, and the specific preparation includes the following steps: S1, Synthesis of quaternary ammonium salt intermediate-1: Weigh 50 mmol of N,N-dimethylethanolamine and 50 mmol of 1-bromododecane, dissolve them in 100 mL of acetone, and carry out the first reaction. Under the condition of reflux condensation, react at 60 °C for 12 h, then cool to room temperature, collect the product of the first reaction, filter it, wash the solid with ether, and then dry it to obtain quaternary ammonium salt intermediate-1. The infrared spectrum is as shown in Figure 1 the a line of, 722 cm - ⁻¹ (in-plane bending vibration of long carbon chain methylene group), 1463 cm - ⁻¹ (C-H bending vibration of long carbon chain), 2850 cm - ⁻¹ (symmetric C-H stretching vibration) and 2920 cm - ⁻¹ (asymmetric C-H stretching vibration); S2, Synthesis of quaternary ammonium salt monomer MQ-1: Weigh 40 mmol of quaternary ammonium salt intermediate-1, 40 mmol of isocyanatoethyl methacrylate, 0.04 mmol of inhibitor p-methoxyphenol, and 20 μL of catalyst dibutyltin dilaurate into a round-bottom flask, add 100 mL of acetone, and carry out the second reaction. React at 45 °C for 12 h, cool to room temperature, evaporate the solvent, and perform solid-liquid separation to obtain quaternary ammonium salt monomer MQ-1; The prepared quaternary ammonium salt monomer MQ-1 was subjected to infrared spectroscopy and nuclear magnetic resonance tests. The infrared spectroscopy test is as Figure 1 shown in line b of -1 , with new vibration peaks appearing at 1717 cm -1 (attributed to the carbonyl group), 1634 cm -1 (attributed to the carbon-carbon double bond), and 1157 cm -1 (attributed to the C-O-C structure). There is no characteristic absorption peak of the isocyanate group near 2272 cm -1 , indicating that the isocyanate group of isocyanatoethyl methacrylate has completely reacted with the hydroxyl group of the quaternary ammonium salt intermediate, and the carbamate group and methacrylate group have been successfully introduced into the molecular structure on the quaternary ammonium salt intermediate; the nuclear magnetic resonance test spectrum is as Figure 2 shown. The hydrogen assignments of MQ-1 are as follows: 0.85 (3H, qH), 1.22 (18H, pH), 1.71 - 1.72 (2H, nH), 1.90 (3H, cH), 3.42 (8H, jH, kH, mH), 3.54 - 3.57 (2H, eH), 3.92 - 3.93 (2H, iH), 4.21 (2H, gH), 4.53 - 4.54 (2H, dH), 5.56 (1H, bH), 6.11 (1H, aH), 6.64 (1H, fH); S3, Synthesis of hydrogel: Weigh 2.5 mmol of quaternary ammonium salt monomer MQ-1, 17.5 mmol of acrylamide, 0.1 mmol of potassium persulfate, 0.01 mmol of methylene bisacrylamide, 0.8 g of sodium dodecyl sulfate, and 20 mmol of sodium chloride into 10 mL of deionized water, stir magnetically for 10 min. After the components are evenly dispersed, introduce nitrogen into the system, remove the bubbles by ultrasonic treatment, transfer to an oven, and carry out the polymerization reaction. React at 35 °C for 8 h to obtain the quaternary ammonium salt hydrogel HMQ-1 with a carbamate structure; The obtained quaternary ammonium salt hydrogel HMQ-1 with a carbamate structure was subjected to infrared spectroscopy test. As Figure 1 shown in line c of -1 , it can be seen from the figure that there is no absorption peak at 1634 cm -1 (attributed to the carbon-carbon double bond) in the infrared spectrum, indicating that the monomers have been successfully polymerized; The quaternary ammonium salt hydrogel HMQ-1 with a carbamate structure was placed in liquid nitrogen for pre-freezing and shaping for 5 min, and then quickly transferred to a freeze dryer for drying. After spraying gold on the surface of the sample for 30 s, the surface morphology of the hydrogel was observed using a scanning electron microscope. The results are as Figure 3 shown. As can be seen from Figure 3 , a cross-linked network structure is formed inside the hydrogel, and there are highly connected and abundant pores inside, which is beneficial to the migration of conductive ions and improves the conductivity of the hydrogel.

[0057] Example 2 This example provides a quaternary ammonium salt hydrogel with a carbamate structure. The specific preparation includes the following steps: S1, Synthesis of quaternary ammonium salt intermediate-2: Weigh 50 mmol of N,N-dimethylethanolamine and 50 mmol of 1-bromotetradecane and dissolve them in 100 mL of acetone. Carry out the first reaction. Under reflux condensation, react at 55 °C for 10 h, then cool to room temperature. Collect the product of the first reaction, filter it, wash the solid with ether, and then dry it to obtain quaternary ammonium salt intermediate-2; S2, Synthesis of quaternary ammonium salt monomer MQ-2: Weigh 40 mmol of quaternary ammonium salt intermediate-2, 40 mmol of isocyanatoethyl methacrylate, 0.04 mmol of inhibitor p-benzenediol, and 20 μL of catalyst dibutyltin dilaurate in a round-bottom flask. Add 100 mL of acetone and carry out the second reaction. React at 50 °C for 9 h, cool to room temperature, evaporate the solvent for solid-liquid separation, and obtain quaternary ammonium salt monomer MQ-2; S3, Synthesis of hydrogel: Weigh 5 mmol of quaternary ammonium salt monomer MQ-2, 15 mmol of acrylamide, 0.1 mmol of potassium persulfate, 0.02 mmol of methylene bisacrylamide, 1 g of sodium dodecyl sulfonate, and 25 mmol of sodium bromide in 10 mL of deionized water. Stir magnetically for 10 min. After each component is evenly dispersed, bubble nitrogen into the system, ultrasonically remove the bubbles, transfer to an oven, and carry out a polymerization reaction. React at 35 °C for 10 h to obtain the quaternary ammonium salt hydrogel HMQ-2 with a carbamate structure.

[0058] Example 3 This example provides a quaternary ammonium salt hydrogel with a carbamate structure. The specific preparation includes the following steps: S1, Synthesis of quaternary ammonium salt intermediate-3: Weigh 50 mmol of N,N-dimethylethanolamine and 50 mmol of 1-bromohexadecane and dissolve them in 100 mL of acetone. Carry out the first reaction. Under reflux condensation, react at 50 °C for 12 h, then cool to room temperature. Collect the product of the first reaction, filter it, wash the solid with ether, and then dry it to obtain quaternary ammonium salt intermediate-3; S2. Synthesis of quaternary ammonium salt monomer MQ-3: Weigh 40 mmol of quaternary ammonium salt intermediate-3, 40 mmol of isocyanatoethyl methacrylate, 0.04 mmol of inhibitor catechol, and 20 μL of catalyst dibutyltin dilaurate into a round-bottom flask, add 100 mL of acetone, conduct the second reaction, react at 50 °C for 10 h, cool to room temperature, evaporate the solvent and perform solid-liquid separation to obtain quaternary ammonium salt monomer MQ-3; S3. Synthesis of hydrogel: Weigh 2.5 mmol of quaternary ammonium salt monomer MQ-3, 17.5 mmol of methacrylamide, 0.1 mmol of ammonium persulfate, 0.01 mmol of methylene bisacrylamide, 0.6 g of cetyltrimethylammonium bromide, and 30 mmol of potassium chloride into 10 mL of deionized water, stir magnetically for 10 min. After the components are evenly dispersed, bubble nitrogen into the system, ultrasonically remove the bubbles, transfer to an oven, and conduct the polymerization reaction. React at 45 °C for 8 h to obtain quaternary ammonium salt hydrogel HMQ-3 with a carbamate structure.

[0059] Example 4 This example provides a quaternary ammonium salt hydrogel with a carbamate structure. The specific preparation includes the following steps: S1. Synthesis of quaternary ammonium salt intermediate-4: Weigh 50 mmol of N,N-dimethylethanolamine and 50 mmol of 1-bromodecane and dissolve them in 100 mL of acetone. Conduct the first reaction. Under the condition of reflux condensation, react at 60 °C for 6 h, then cool to room temperature, collect the product of the first reaction, filter it, wash the solid with ether, and then dry it to obtain quaternary ammonium salt intermediate-4; S2. Synthesis of quaternary ammonium salt monomer MQ-4: Weigh 40 mmol of quaternary ammonium salt intermediate-4, 40 mmol of isocyanatoethyl methacrylate, 0.04 mmol of inhibitor catechol, and 20 μL of catalyst dibutyltin dilaurate into a round-bottom flask, add 100 mL of acetone, conduct the second reaction, react at 55 °C for 12 h, cool to room temperature, evaporate the solvent and perform solid-liquid separation to obtain quaternary ammonium salt monomer MQ-4; S3. Synthesis of hydrogel: Weigh 2.5 mmol of quaternary ammonium salt monomer MQ-4, 17.5 mmol of acrylamide, 0.1 mmol of potassium persulfate, 0.01 mmol of methylene bisacrylamide, 0.9 g of sodium dodecylsulfonate, and 10 mmol of lithium chloride into 10 mL of deionized water, stir magnetically for 10 min. After the components are evenly dispersed, bubble nitrogen into the system, ultrasonically remove the bubbles, transfer to an oven, and conduct the polymerization reaction. React at 50 °C for 8 h to obtain quaternary ammonium salt hydrogel HMQ-4 with a carbamate structure.

[0060] Example 5 This example provides a quaternary ammonium salt hydrogel with a carbamate structure. The specific preparation includes the following steps: In the same manner as in Example 1, except that "2.5 mmol of quaternary ammonium salt monomer MQ-1 and 17.5 mmol of acrylamide" is changed to "5 mmol of quaternary ammonium salt monomer MQ-1 and 15 mmol of acrylamide", to obtain a quaternary ammonium salt hydrogel HMQ-5 with a carbamate structure.

[0061] Example 6 This example provides a quaternary ammonium salt hydrogel with a carbamate structure. The specific preparation includes the following steps: In the same manner as in Example 1, except that "2.5 mmol of quaternary ammonium salt monomer MQ-1 and 17.5 mmol of acrylamide" is changed to "1 mmol of quaternary ammonium salt monomer MQ-1 and 19 mmol of acrylamide", to obtain a quaternary ammonium salt hydrogel HMQ-6 with a carbamate structure.

[0062] Comparative Example 1 This comparative example provides a hydrogel. The specific preparation includes the following steps: Weigh 20 mmol of acrylamide, 0.1 mmol of potassium persulfate, and 0.01 mmol of methylene bisacrylamide into 10 mL of deionized water, stir magnetically for 10 min. After each component is evenly dispersed, bubble nitrogen into the system, remove the bubbles by ultrasonic treatment, transfer to an oven, and carry out a polymerization reaction. React at 35 °C for 8 h to obtain hydrogel PAM-1.

[0063] Comparative Example 2 This comparative example provides a hydrogel. The specific preparation includes the following steps: S1. In the same manner as in step S1 of Example 6; S2. Synthesis of quaternary ammonium salt monomer MQ-1: Weigh 40 mmol of quaternary ammonium salt intermediate-1 into a round-bottom flask, and add 100 mL of tetrahydrofuran; weigh 40 mmol of methacryloyl chloride and 0.04 mmol of inhibitor p-methoxyphenol into a constant-pressure dropping funnel, and add 100 mL of tetrahydrofuran; magnetically stir the round-bottom flask in an ice bath, continuously add the solution in the constant-pressure funnel to the round-bottom flask for the second reaction, control the dropping time within 45 min. After the dropping is completed, continue to maintain the ice bath and magnetic stirring conditions, and react for 6 h. After the reaction is completed, adjust the pH of the solution to 7 with 0.5 mol / L sodium hydroxide solution, distill off tetrahydrofuran under reduced pressure, then add 100 mL of ethyl acetate three times for extraction and liquid separation, collect the oil phase and add an appropriate amount of sodium sulfate to dry overnight, filter, take the filtrate, and distill off the solvent under reduced pressure to obtain quaternary ammonium salt monomer MQ-D2; S3. In the same manner as in step S3 of Example 6, except that "quaternary ammonium salt monomer MQ-1" is changed to "quaternary ammonium salt monomer MQ-D2", to obtain a quaternary ammonium salt hydrogel HMQ-D2 with a carbamate structure.

[0064] Comparative Example 3 This comparative example provides a hydrogel, and the specific preparation includes the following steps: In the same manner as in Example 6, except that "N,N-dimethylethanolamine" is changed to "5-dimethylamino-1-pentanol".

[0065] Comparative Example 4 This comparative example provides a hydrogel, and the specific preparation includes the following steps: In the same manner as in Example 6, except that "1-bromododecane" is changed to "1-bromohexane", to obtain a quaternary ammonium salt hydrogel HMQ-D4 with a carbamate structure.

[0066] Comparative Example 5 This comparative example provides a hydrogel, and the specific preparation includes the following steps: In the same manner as in Example 6, except that "1-bromododecane" is changed to "1-bromoeicosane", to obtain a quaternary ammonium salt hydrogel HMQ-D5 with a carbamate structure.

[0067] Test Example 1 The mechanical strength test method of the hydrogel is as follows: Prepare the hydrogel sample into a spline with a length of 35 mm, a width of 10 mm, and a thickness of 1 mm for waiting for testing. Use a universal tensile machine to conduct a tensile test on the hydrogel, and the test conditions are as follows: the temperature is 25 °C, the gauge length L0 is 20 mm, and the tensile rate is 100 mm / min. Record the following key data: the maximum tensile force (F max ), the displacement at break (ΔL), and calculate the initial cross-sectional area A (width × thickness) of the sample; The specific calculation formula is as follows: Elongation at break: ε = ΔL / L0 × 100%; Tensile strength: σ = F max / A; The specific test results are shown in Table 1.

[0068] Table 1 Mechanical strength of the hydrogels of the examples and comparative examples

[0069] The tensile strength of the existing hydrophobic associating antibacterial hydrogel without a carbamate structure is 307 KPa, and the quaternary ammonium salt hydrogel with a carbamate structure prepared in the present invention has a higher tensile strength.

[0070] Test Example 2 The hydrogels prepared in the examples and comparative examples were combined with 1 mL of bacterial suspension (the concentration of Gram-positive Staphylococcus aureus was 1×10 6 CFU / mL, and the concentration of Gram-negative Escherichia coli was 1×10 6 CFU / mL) and cultured at 37 °C for 4 h. Subsequently, they were cultured on an LB agar plate (specific composition: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, 15 g / L agar powder) at 37 °C for 24 h. The test was repeated 3 times, and the average value was taken to calculate the bacterial survival rate. The calculation formula was bacterial survival rate (%) = (number of colonies in the experimental group / number of colonies in the control group) × 100%. The specific test results are shown in Table 2.

[0071] Table 2 Bacterial survival rates in the examples and comparative examples

[0072] The results showed that the quaternary ammonium salt hydrogels with a carbamate structure in the examples had excellent antibacterial properties. Especially for Example 1, it had the best antibacterial effect, and the bacterial survival rate was reduced to 11%.

[0073] Test Example 3 Part of the hydrogel samples of the examples and Comparative Example 1 were respectively placed in a 96-well microplate medium containing cells. The cell type was mouse fibroblasts, and the cell concentration was 5000 cells / well. The cells were cultured in an incubator at 37 °C and 5% CO2 for 5 days. The CCK-8 method was used to determine the cell survival rate. The specific test method was as follows: 10 μL of CCK-8 reagent was added to each well, and incubation was continued for 3 h. Then, the absorbance (OD value) was measured at a wavelength of 450 nm using an enzyme-linked immunosorbent assay (ELISA) reader; the cell survival rate (%) was calculated as (OD value of the experimental group - OD value of the blank group) / OD value of the control group × 100%; the biocompatibility of the hydrogel was evaluated. If the cell survival rate in the experimental group was close to or higher than 90%, it indicated that the hydrogel had good biocompatibility; if it was significantly lower than 70%, there might be toxicity; the specific test results are shown in Figure 4 , as Figure 4 shown. Compared with the comparative examples, the cell survival rate in the examples was higher, showing good biocompatibility. The hydrogel of the present invention had good safety in biological applications.

[0074] Test Example 4 Under the conditions of a temperature of 25 °C and a humidity of 50%, cyclic tensile experiments with a maximum strain of 300% were carried out on Examples 1-6 and Comparative Example 1, and the residual strain changes after different time intervals were recorded.

[0075] The results are as Figure 5As shown in (II) of [description], the hydrogel samples of Examples 1-6 showed low residual strain during cyclic stretching after a short interval, indicating excellent self-recovery performance. In contrast, the residual strain of PAM-1 in Comparative Example 1 was significantly higher, suggesting that the hydrogels of the present invention have better adaptability in dynamic applications and enhanced potential for application in stretch sensors.

[0076] Test Example 5 Under the conditions of a temperature of 25 °C and a humidity of 50%, the water retention performance of the hydrogels of Examples 1-6 and Comparative Example 1 was tested, and the weight changes were recorded. The test results are as Figure 6 shown in (II) of [description]. It can be seen from the figure that the weight fluctuations of the hydrogel samples of Examples 1-6 were small, indicating that the water retention performance of the hydrogel samples of the examples was significantly better than that of Comparative Example 1, and the proportion of maintaining the original weight was as high as 83%. This shows that the hydrogels of the present invention have excellent water retention ability in long-term applications. Hydrogels with strong water retention ability can maintain conductivity and sensitivity during long-term movement, ensuring that the sensor can accurately capture movement signals and have the potential for long-term application as a motion detection sensor.

[0077] Test Example 6 The conductivity of the hydrogel sample HMQ-2 prepared in Example 2 was tested for a flexible motion sensor; as Figure 7 shown, after HMQ-2 was connected to the circuit, the LED lamp beads could be lit, indicating that the quaternary ammonium salt hydrogel with a urethane structure prepared in the present invention has good conductivity.

[0078] The stability of the hydrogel sample HMQ-2 prepared in Example 2 was tested for a flexible strain sensor; as Figure 8 shown, under the condition of a stretching range of 50%, after 300 cycles of cyclic stretching, the range of the resistance change rate curve of the hydrogel remained basically unchanged, indicating that the sensor prepared in the present invention has excellent stability and dynamic durability and has the potential for application as a motion detection sensor.

[0079] Test Example 7 A human motion monitoring experiment was carried out. The HMQ-2 sample of Example 2 was attached to various parts of the human body, and its two ends were connected to a digital ammeter through copper wires to record the resistance change of the hydrogel during human movement. Figure 9The curve of the relative resistance (ΔR / R0) of the hydrogel sample during human movement is shown. The experimental results show that when the human joint starts to move, the relative resistance of the hydrogel increases accordingly and reaches a peak when the joint movement reaches the maximum amplitude; subsequently, when the joint returns to the initial position, the relative resistance of the hydrogel decreases correspondingly. It is worth noting that during the process of continuously repeating the same action, the sensor can generate a stable and consistent response signal, fully demonstrating that the hydrogel sample has excellent strain sensitivity, fast response characteristics, and good repeatability.

[0080] Obviously, the above embodiments are only examples given for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A quaternary ammonium salt containing a carbamate structure, characterized in that, The structural formula of the quaternary ammonium salt is as follows: ； Wherein, n includes an integer from 7 to 17; m includes an integer from 2 to 4; X includes Cl, Br, I, F.

2. A method for preparing a quaternary ammonium salt containing a carbamate structure according to claim 1, characterized in that, It includes the following steps: S1, Mix N,N-dimethylaminoalkyl alcohol, haloalkane, and solvent A for the first reaction, and perform solid-liquid separation to obtain a quaternary ammonium salt intermediate. S2, Mix the quaternary ammonium salt intermediate, isocyanatoethyl methacrylate, inhibitor, catalyst, and solvent B for the second reaction, and perform solid-liquid separation to obtain a quaternary ammonium salt containing a carbamate structure.

3. The preparation method according to claim 2, characterized in that, The N,N-dimethylaminoalkyl alcohol includes at least one of N,N-dimethylethanolamine, N,N-dimethylpropanolamine, and N,N-dimethylbutanolamine; and / or, the haloalkane includes at least one of chloroalkane, bromoalkane, iodoalkane, and fluoroalkane; and / or, the solvent A and solvent B each independently include at least one of ethyl acetate, acetone, butanone, cyclohexanone, and N,N-dimethylformamide; and / or, the temperature of the first reaction is 45-60 °C, and the time is 6-12 h.

4. The preparation method according to claim 3, characterized in that, The chloroalkane includes at least one of 1-chlorooctane, 1-chlorononane, 1-chlorodecane, 1-chloroundecane, 1-chlorododecane, 1-chlorotridecane, 1-chlorotetradecane, 1-chloropentadecane, 1-chlorohexadecane, 1-chloroheptadecane, and 1-chlorooctadecane; and / or, the bromoalkane includes at least one of 1-bromooctane, 1-bromononane, 1-bromodecane, 1-bromoundecane, 1-bromododecane, 1-bromotridecane, 1-bromotetradecane, 1-bromopentadecane, 1-bromohexadecane, 1-bromoheptadecane, and 1-bromooctadecane; and / or, the iodoalkane includes at least one of 1-iodooctane, 1-bromononane, 1-iododecane, 1-iodoundecane, 1-iodododecane, 1-iodotridecane, 1-iodotetradecane, 1-iodopentadecane, 1-iodohexadecane, 1-iodoheptadecane, and 1-iodooctadecane; and / or, the fluoroalkane includes at least one of 1-fluorooctane, 1-fluorononane, 1-fluorodecane, 1-fluoroundecane, 1-fluorododecane, 1-fluorotridecane, 1-fluorotetradecane, 1-fluoropentadecane, 1-fluorohexadecane, 1-fluoroheptadecane, and 1-fluorooctadecane.

5. The preparation method according to claim 2, wherein The inhibitor includes at least one of phenolic compounds or quinone compounds; and / or, based on the molar amount of isocyanatoethyl methacrylate, the dosage of the inhibitor is 0.1-0.3 mol%; and / or, the catalyst includes an organotin salt; and / or, the dosage ratio of isocyanatoethyl methacrylate to the catalyst is 1 mmol:(0.5-1) μL; and / or, the temperature of the second reaction is 45-55 °C, and the time is 9-12 h.

6. The preparation method according to claim 5, characterized in that, The inhibitor includes at least one of hydroquinone, p-methoxyphenol, p-benzoquinone, and methylhydroquinone; and / or, the catalyst includes at least one of dibutyltin dilaurate and stannous octoate.

7. A preparation method of a quaternary ammonium salt hydrogel containing a carbamate structure, characterized in that, It includes the following steps: Mix a quaternary ammonium salt monomer, an amide group-containing monomer, an initiator, a crosslinking agent, an emulsifier, an inorganic salt, and water to obtain a mixed solution, and perform a polymerization reaction to obtain a quaternary ammonium salt hydrogel with a carbamate structure. Among them, the quaternary ammonium salt monomer is the quaternary ammonium salt containing a carbamate structure as described in claim 1 or the quaternary ammonium salt containing a carbamate structure prepared by the preparation method described in any one of claims 2-6.

8. The preparation method according to claim 7, characterized in that, The amide group-containing monomer includes at least one of acrylamide, methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-vinyl-N-methylacetamide, N-ethylacrylamide, N,N-dimethylmethacrylamide; and / or, the molar ratio of the quaternary ammonium salt monomer to the amide group-containing monomer is 1:3-19; and / or, based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer, the dosage of the initiator is 0.05-0.1 mol%; and / or, based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer, the dosage of the crosslinking agent is 0.03-0.2 mol%; and / or, based on the mass of the mixed solution, the concentration of the emulsifier is 60-100 g / L; and / or, based on the mass of the mixed solution, the concentration of metal ions in the inorganic salt is 1-3 mol / L; and / or, the ratio of the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer to the amount of water used is (1.50-3.00) mmol:1 mL; and / or, the temperature of the polymerization reaction is 35-50 °C and the time is 8-12 h; and / or, the initiator includes persulfate; and / or, the crosslinking agent includes methylene bisacrylamide; and / or, the emulsifier includes sulfonate; and / or, the inorganic salt includes at least one of chloride salts and bromide salts.

9. A quaternary ammonium salt hydrogel containing a carbamate structure prepared by the preparation method described in any one of claims 7-8.

10. An antibacterial material, characterized in that, The antibacterial material includes the quaternary ammonium salt hydrogel containing a carbamate structure described in claim 9.

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