A quaternary ammonium salt containing a carbamate structure and its preparation method and application

Abstract

The present invention belongs to the field of hydrogel sensor technology and specifically relates to a quaternary ammonium salt containing a carbamate structure, its preparation method, and application. The structural formula of the quaternary ammonium salt is: wherein n includes an integer of 7-17; m includes an integer of 2-4; and X includes Cl, Br, I, or F. The quaternary ammonium salt contains a carbamate group capable of forming hydrogen bonds, resulting in the quaternary ammonium salt and the resulting hydrogel having excellent hydrophilicity and water retention. The prepared hydrogel has excellent fatigue resistance, tensile hysteresis, biocompatibility, and antibacterial properties.

Description

Technical Field

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

[0002] Conventional sensor materials have significant deficiencies in antimicrobial performance and mechanical strength, particularly in humid or biological environments. These strength and stability deficiencies in conventional hydrogel sensor materials often limit their lifespan and reliability in practical applications. Existing hydrogels still need to be improved in terms of antimicrobial efficacy, response speed, and adaptability to application environments. Therefore, research and development of antimicrobial hydrogels has become a key area of ​​materials science.

[0003] Antimicrobial hydrogel sensors combine the biocompatibility and flexibility of hydrogel materials with antimicrobial components to meet safety requirements. Currently, most research focuses on introducing antimicrobial agents through physical or chemical doping to enhance antimicrobial properties, such as adding silver ions and antimicrobial peptides. However, some antimicrobial additives may cause biocompatibility issues, especially in medical and biosensing applications. Improper use of antimicrobial agents may cause local toxic reactions, limiting their feasibility in practical applications.

[0004] Another approach to achieving antibacterial properties is to use quaternary ammonium salts as a backbone. However, longer hydrophobic chains reduce the water solubility of the quaternary ammonium salt monomer, affecting its addition amount to the hydrogel and limiting its addition amount. Excessively long hydrophobic chains can also reduce the interaction between the hydrophilic network within the hydrogel, leading to a decrease in antibacterial 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 existing hydrogels containing antibacterial agents, such as poor biocompatibility, insufficient antibacterial and mechanical properties of hydrogels containing quaternary ammonium salt groups, and limited addition amount of quaternary ammonium salts due to excessively long chain segments, thereby providing a quaternary ammonium salt containing a carbamate structure, a preparation method thereof, and an application thereof.

[0006] To this end, the present invention provides the following technical solutions:

[0007] 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:

[0008] ;

[0009] wherein n includes an integer of 7-17; m includes an integer of 2-4; and X includes Cl, Br, I, and F.

[0010] The second aspect of the present invention is to provide a method for preparing the aforementioned quaternary ammonium salt containing a carbamate structure, which comprises the following steps:

[0011] S1, mixing N,N-dimethylaminoalkyl alcohol, halogenated alkane, and solvent A for a first reaction, and performing solid-liquid separation to obtain a quaternary ammonium salt intermediate;

[0012] S2, mixing the quaternary ammonium salt intermediate, isocyanoethyl methacrylate, a polymerization inhibitor, a catalyst and solvent B to carry out a second reaction, and performing solid-liquid separation to obtain a quaternary ammonium salt containing a carbamate structure.

[0013] In the present invention, taking N,N-dimethylethanolamine and 1-chlorooctane as examples, the specific reaction chemical formula is as follows:

[0014] First is the S1 reaction,

[0015] ;

[0016] The S1 reaction is the synthesis of quaternary ammonium salt intermediates, which undergoes nucleophilic substitution through the SN2 mechanism. The nitrogen atom containing a lone pair of electrons in the N,N-dimethylethanolamine molecule acts as a nucleophile to attack the partially positively charged primary carbon atom in the chloroalkane. At the same time, the chloride ion leaves as a leaving group, ultimately generating a quaternary ammonium salt intermediate.

[0017] Then comes the S2 reaction.

[0018] ;

[0019] The S2 reaction is a nucleophilic addition process between an isocyanate group and an alcohol hydroxyl group: the hydroxyl group (-OH) in the quaternary ammonium salt molecule acts as a nucleophilic reagent to attack the central carbon atom of the isocyanate group (-N=C=O) in the isocyanoethyl methacrylate molecule to form a carbamate group (-NH-COO-), and finally obtain a quaternary ammonium salt containing a carbamate structure.

[0020] In the present invention, after the first reaction is completed, the mixture is cooled to room temperature and then subjected to post-treatment; after the second reaction is completed, the mixture is cooled to room temperature and then subjected to solid-liquid separation. Typically, but not limitedly, the solid-liquid separation is performed by evaporating the solvent.

[0021] 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.

[0022] According to the present invention, the halogenated alkane includes at least one of chloroalkane, bromoalkane, iodoalkane and fluoroalkane.

[0023] According to the present invention, the chlorinated alkane 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.

[0024] According to the present invention, the brominated alkane includes at least one of 1-bromooctane, 1-bromononane, 1-bromodecane, 1-bromonoundecane, 1-bromododecane, 1-bromodridecane, 1-bromodetetradecane, 1-bromopentadecane, 1-bromohexadecane, 1-bromoheptadecane and 1-bromooctadecane.

[0025] According to the present invention, the iodinated alkane 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.

[0026] 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.

[0027] According to the present invention, the solvent A and the solvent B each independently include at least one of ethyl acetate, acetone, butanone, cyclohexanone and N,N-dimethylformamide.

[0028] According to the present invention, in step S1, the usage ratio of the halogenated alkane to the solvent A is 1 mmol:(2-3) mL.

[0029] According to the present invention, in step S2, the usage ratio of the quaternary ammonium salt intermediate to the solvent B is 1 mmol:(2-3) mL.

[0030] In the present invention, in fact, the N,N-dimethylaminoalkyl alcohol and the halogenated alkane are reacted in a molar ratio of 1:1. In order to ensure the smooth progress of the reaction, the halogenated alkane is slightly excessive. When added, the N,N-dimethylaminoalkyl alcohol and the halogenated alkane are generally added in a molar ratio of 1:1-1.05.

[0031] According to the present invention, the temperature of the first reaction is 45-60° C. and the time is 6-12 hours.

[0032] In step S1 of the present invention, the product after the first reaction is collected for solid-liquid separation, and an ether reagent is used to wash and separate the solid to remove impurities, and the solid is dried to obtain a quaternary ammonium salt intermediate; the ether reagent is a conventional reagent in the art, typically but not limited to, the ether reagent includes diethyl ether and / or methyl ethyl ether; the solid-liquid separation is performed by filtration; and the unreacted substance is washed and removed by the ether reagent.

[0033] According to the present invention, the polymerization inhibitor includes at least one of phenolic compounds or quinone compounds; optionally, the polymerization inhibitor includes at least one of hydroquinone, p-methoxyphenol, p-benzoquinone, and methylhydroquinone; further optionally, the polymerization inhibitor includes p-methoxyphenol.

[0034] In the present invention, the quaternary ammonium salt intermediate and isocyanoethyl methacrylate are actually reacted in a molar ratio of 1:1, but in order to facilitate the reaction, a slightly excessive amount of the quaternary ammonium salt intermediate is added.

[0035] According to the present invention, the amount of the polymerization inhibitor used is 0.1-0.3 mol % based on the molar amount of isocyanoethyl methacrylate.

[0036] According to the present invention, the catalyst includes a tin-containing organic salt; optionally, the catalyst includes at least one of dibutyltin dilaurate and stannous octoate; further optionally, the catalyst includes dibutyltin dilaurate.

[0037] According to the present invention, the usage ratio of isocyanoethyl methacrylate to catalyst is 1 mmol: (0.5-1) μL.

[0038] According to the present invention, the temperature of the second reaction is 45-55° C. and the time is 9-12 hours.

[0039] In the present invention, the mixing in step S1 and the mixing in step S2 are conventional mixing in the art, and they only need to be mixed uniformly.

[0040] A third aspect of the present invention provides a method for preparing a quaternary ammonium salt hydrogel containing a carbamate structure, comprising 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;

[0041] Wherein, the quaternary ammonium salt monomer is the aforementioned quaternary ammonium salt containing a carbamate structure or the quaternary ammonium salt containing a carbamate structure obtained by the aforementioned preparation method.

[0042] 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. The specific reaction chemical formula is as follows: ; is the chain segment extension direction, As the connection site, the hydrogel is prepared as a free radical micelle copolymerization reaction; among them, the emulsifier forms micelles in water, which serves as a solubilization site for the quaternary ammonium salt monomer, and the inorganic salt improves the solubilization effect of the micelles; and the amide-containing monomer and initiator are dissolved in the aqueous solution to carry out free radical polymerization.

[0043] Among them, the free radical polymerization reaction is mainly divided into three stages: (1) Under heating conditions, the initiator decomposes to generate free radicals, which attack the -C=C- double bond in the amide-containing monomer to form new free radicals, thereby initiating the polymerization of the amide-containing monomer and generating active macromolecules with free radical chain ends; (2) When the active macromolecular chain with free radical chain ends encounters a micelle with a solubilized quaternary ammonium salt monomer, it will enter the micelle and initiate polymerization with the quaternary ammonium salt monomer; since each micelle can solubilize multiple quaternary ammonium salt monomers, the long carbon chains of these quaternary ammonium salt monomers will spontaneously entangle and gradually form hydrophobic association microdomains; (3) When the monomer reaction in a micelle is complete, the active macromolecular chain with free radical chain ends leaves the micelle and continues to initiate the polymerization of the amide-containing monomer in the aqueous phase until it encounters the next solubilized micelle. During the polymerization process, when the active macromolecular chain encounters a crosslinker, it will attack the -C=C- double bond in the crosslinker to form a chemical crosslinking network. The termination of the polymerization reaction may be achieved through free radical coupling, chain termination and chain transfer, ultimately forming a cross-linked copolymer.

[0044] 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 the water, the steps of introducing nitrogen into the system and removing bubbles by ultrasonication are also included to avoid the presence of bubbles in the hydrogel after polymerization and affecting its mechanical properties.

[0045] According to the present invention, the amide group-containing monomer includes at least one of acrylamide, methacrylamide, N-hydroxymethyl acrylamide, N-hydroxymethyl methacrylamide, N-vinyl-N-methylacetamide, N-ethyl acrylamide, and N,N-dimethyl methacrylamide; optionally, the amide group-containing monomer includes acrylamide.

[0046] According to the present invention, the molar ratio of the quaternary ammonium salt monomer to the amide group-containing monomer is 1:3-19; alternatively, the molar ratio of the quaternary ammonium salt monomer to the amide group-containing monomer is 1:5-10.

[0047] 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.

[0048] According to the present invention, the amount of the initiator used is 0.05-0.1 mol %, based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer.

[0049] In the present invention, the cross-linking agent includes methylene bisacrylamide; methylene bisacrylamide is a common cross-linking agent for preparing hydrogels. Although it is slightly soluble in the solution, due to its small dosage, a small amount of addition can also achieve cross-linking.

[0050] According to the present invention, the amount of the cross-linking agent is 0.03-0.2 mol %, based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer.

[0051] According to the present invention, the emulsifier includes sulfonate; optionally, the emulsifier includes at least one of sodium dodecyl sulfonate and sodium dodecylbenzene sulfonate; further optionally, the emulsifier includes sodium dodecyl sulfonate.

[0052] 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.

[0053] According to the present invention, the inorganic salt includes chloride salt and / or bromide salt; 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.

[0054] 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 optionally 2-2.5 mol / L.

[0055] According to the present invention, the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer and the usage ratio of water is (1.50-3.00) mmol:1 mL.

[0056] According to the present invention, the polymerization reaction temperature is 35-50° C. and the time is 8-12 hours.

[0057] The fourth aspect of the present invention protects a quaternary ammonium salt gel containing a carbamate structure obtained by the aforementioned preparation method.

[0058] A fifth aspect of the present invention provides an antibacterial material, wherein the antibacterial material comprises the aforementioned quaternary ammonium salt gel containing a carbamate structure.

[0059] According to the present invention, the antibacterial material is used in a sensor.

[0060] The technical solution of the present invention has the following advantages:

[0061] 1. The present invention provides a quaternary ammonium salt containing a carbamate structure, wherein the structural formula of the quaternary ammonium salt monomer is: ;

[0062] wherein n includes an integer of 7-17; m includes an integer of 2-4; X includes Cl, Br, I, and F; the specific structure of the quaternary ammonium salt of the present invention has good hydrophilicity and can be smoothly prepared into a hydrogel without the defect of limited addition amount; and the presence of the double bond can give the quaternary ammonium salt monomer 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'-), which has a strong polarity and is prepared into a hydrogel, and forms strong intramolecular and intermolecular hydrogen bonds with amino groups, carbonyl groups, and the like in the hydrogel, significantly improving 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 fatigue resistance 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 carbamate, the hydrogel can be given excellent biocompatibility. The quaternary ammonium salt group can effectively adsorb negatively charged bacteria through electrostatic attraction, hydrogen bonding and hydrophobic interaction between surfactant molecules and proteins, ultimately leading to their death, thereby giving the hydrogel excellent antibacterial properties.

[0063] 2. The present invention provides a method for preparing a quaternary ammonium salt containing a carbamate structure. First, N,N-dimethylaminoalkyl alcohol, alkyl halide, and solvent A are mixed to carry out a first reaction, followed by solid-liquid separation to obtain a quaternary ammonium salt intermediate, wherein the amino group of the N,N-dimethylaminoalkyl alcohol reacts with the alkyl halide to generate a quaternary ammonium salt intermediate; then, the quaternary ammonium salt intermediate, isocyanoethyl methacrylate, a polymerization inhibitor, a catalyst, and solvent B are mixed to carry out a second reaction, wherein in the second reaction, the hydroxyl group of the quaternary ammonium salt intermediate reacts with the isocyanate group in the isocyanoethyl methacrylate to generate a structure containing a carbamate group (-RNHCOOR') and retaining a double bond group capable of further reaction; the step-by-step reaction can effectively avoid side reactions, thereby making the reactants have higher reactivity.

[0064] 3. The specific molar ratio of the quaternary ammonium salt monomer to the amide-containing monomer in the present invention can further improve the antimicrobial properties and mechanical properties of the hydrogel, achieving a balance between these properties. By optimizing the ratio of the quaternary ammonium salt monomer, the antimicrobial effect of the hydrogel is enhanced, making it suitable for use in medical and health fields. A reasonable molar ratio design improves the strength of the hydrogel. By achieving a balance between antimicrobial properties and mechanical properties, it can achieve higher efficiency and a wider range of applications.

[0065] 4. The quaternary ammonium hydrogels containing a carbamate structure prepared by the present invention exhibit multiple interactions. The carbamate structure can form multiple intramolecular and intermolecular hydrogen bonds, giving the hydrogel excellent fatigue resistance; intramolecular chemical crosslinking can provide basic mechanical strength; the long hydrophobic chains of the quaternary ammonium salt monomers and the emulsifier form a hydrophobic associating network in the hydrogel. The dynamic properties of the hydrophobic associating network can significantly enhance the hydrogel's mechanical strength and fatigue resistance; the inorganic salts used to construct the hydrophobic associating network exist in the hydrogel network in ionic form and can act as charge carriers, giving the hydrogel excellent electrical conductivity. The presence of hydrophobic associating microdomains can also enhance the hydrogel's mechanical strength and fatigue resistance; the carbamate structure can increase the water solubility of the quaternary ammonium salt monomer, thereby increasing the amount of quaternary ammonium salt added and further improving the hydrogel's antibacterial properties. The synergistic effect of the carbamate structure and the quaternary ammonium salt group gives the hydrogel significant advantages in fatigue resistance and antibacterial properties, expanding the application range of the hydrogel of the present invention in the field of conductive hydrogel sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0067] Figure 1 The infrared spectra of the quaternary ammonium salt intermediate-1, the quaternary ammonium salt monomer MQ-1 and the quaternary ammonium salt hydrogel HMQ-1 with a carbamate structure prepared in Example 1 of the present invention are shown;

[0068] Figure 2 This is the nuclear magnetic resonance spectrum of the quaternary ammonium salt monomer prepared in Example 1 of the present invention;

[0069] Figure 3 is a scanning electron micrograph of a quaternary ammonium salt hydrogel having a carbamate structure obtained in Example 1 of the present invention;

[0070] Figure 4 The biocompatibility test results of the quaternary ammonium salt hydrogels with carbamate structures prepared in Examples 1-4 of the present invention and Comparative Example 1 are as follows;

[0071] Figure 5 The self-recovery performance test results of the quaternary ammonium salt gels with carbamate structures prepared in Examples 1-6 and Comparative Example 1 of the present invention are shown in FIG. Figure 5 (Ⅰ) in the figure is the overall test result diagram. Figure 5 (II) in Figure 5An enlarged view of the test results of Examples 1-6 in (I);

[0072] Figure 6 The results of comparative test on the water retention performance of the quaternary ammonium salt gels with carbamate structure prepared in Examples 1-6 of the present invention and Comparative Example 1 are shown in FIG. Figure 6 (Ⅰ) in the figure is the overall test result diagram. Figure 6 (II) in Figure 6 An enlarged view of the test results of Examples 1-6 in (I);

[0073] Figure 7 The conductive performance test results of the quaternary ammonium salt gel with a carbamate structure prepared in Example 2 of the present invention are as follows;

[0074] Figure 8 The stability test results of the quaternary ammonium salt gel with a carbamate structure prepared in Example 2 of the present invention when used as a flexible strain sensor;

[0075] Figure 9 This is the conductivity test result of the quaternary ammonium salt gel with a carbamate structure prepared in Example 2 of the present invention when used as a motion monitoring sensor. DETAILED DESCRIPTION

[0076] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0077] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0078] Example 1

[0079] This embodiment provides a quaternary ammonium salt gel with a carbamate structure, which is specifically prepared by the following steps:

[0080] S1, Synthesis of Quaternary Ammonium Salt Intermediate-1: Weigh 50 mmol of N,N-dimethylethanolamine and 50 mmol of 1-bromododecane and dissolve them in 100 mL of acetone to carry out a first reaction. Under condensation reflux, react at 60°C for 12 h, cool to room temperature, collect the product of the first reaction, filter, wash the solid with ether, and then dry to obtain Quaternary Ammonium Salt Intermediate-1. The infrared spectrum is shown in FIG. Figure 1 As shown by line a, 722cm -¹ (in-plane bending vibration of long carbon chain methylene groups), 1463 cm - ¹ (long carbon chain CH bending vibration), 2850 cm - ¹ (symmetric CH stretching vibration) and 2920 cm - ¹ (asymmetric CH stretching vibration);

[0081] S2, Synthesis of Quaternary Ammonium Salt Monomer MQ-1: 40 mmol of quaternary ammonium salt intermediate-1, 40 mmol of isocyanoethyl methacrylate, 0.04 mmol of polymerization inhibitor p-methoxyphenol, and 20 μL of catalyst dibutyltin dilaurate were weighed into a round-bottom flask, 100 mL of acetone was added, and a second reaction was carried out at 45° C. for 12 h. The mixture was cooled to room temperature, and the solvent was evaporated for solid-liquid separation to obtain quaternary ammonium salt monomer MQ-1;

[0082] The prepared quaternary ammonium salt monomer MQ-1 was subjected to infrared spectrum test and nuclear magnetic resonance test. The infrared spectrum test showed that Figure 1 As shown by line b, at 1717cm -1 (attributed to carbonyl), 1634cm -1 (attributed to carbon-carbon double bonds) and 1157 cm -1 A new vibration peak appears at 2272 cm (attributed to the COC structure). -1 There is no characteristic absorption peak of the isocyanate group nearby, which proves that the isocyanate group of isocyanoethyl methacrylate reacts completely with the hydroxyl group of the quaternary ammonium salt intermediate, and the carbamate group and methacrylate group are successfully introduced into the molecular structure of the quaternary ammonium salt intermediate; the NMR test spectrum is shown in Figure 2 As shown, the hydrogen atoms 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);

[0083] S3, synthesis of hydrogel: 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 dodecylsulfonate, and 20 mmol of sodium chloride were weighed and dissolved in 10 mL of deionized water. The mixture was magnetically stirred for 10 min. After the components were uniformly dispersed, nitrogen was bubbled into the system. The bubbles were removed by ultrasonication. The mixture was transferred to an oven for polymerization reaction at 35°C for 8 h to obtain quaternary ammonium salt hydrogel HMQ-1 with a carbamate structure.

[0084] The obtained quaternary ammonium salt gel HMQ-1 with carbamate structure was tested by infrared spectroscopy. Figure 1 As shown by the c line, it can be seen from the figure that the infrared spectrum is at 1634cm -1 There is no absorption peak at the carbon-carbon double bond, which proves that the monomers have been successfully polymerized.

[0085] The quaternary ammonium hydrogel HMQ-1 with carbamate structure was pre-frozen in liquid nitrogen for 5 minutes and quickly transferred to a freeze dryer for drying. After spraying gold on the surface of the sample for 30 seconds, the surface morphology of the hydrogel was observed using a scanning electron microscope. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that a cross-linked network structure is formed inside the hydrogel, and there are abundant and highly connected pores inside, which is conducive to the migration of conductive ions and improves the conductivity of the hydrogel.

[0086] Example 2

[0087] This embodiment provides a quaternary ammonium salt gel with a carbamate structure, which is specifically prepared by the following steps:

[0088] 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 to carry out a first reaction. The reaction is carried out at 55° C. under condensation reflux for 10 h, and then cooled to room temperature. The product of the first reaction is collected and filtered. The solid is washed with ether and then dried to obtain Quaternary Ammonium Salt Intermediate-2;

[0089] S2, Synthesis of quaternary ammonium salt monomer MQ-2: 40 mmol of quaternary ammonium salt intermediate-2, 40 mmol of isocyanoethyl methacrylate, 0.04 mmol of polymerization inhibitor p-pyrocatechol, and 20 μL of catalyst dibutyltin dilaurate were weighed into a round-bottom flask, 100 mL of acetone was added, and a second reaction was carried out at 50° C. for 9 h. The mixture was cooled to room temperature, and the solvent was evaporated for solid-liquid separation to obtain quaternary ammonium salt monomer MQ-2;

[0090] S3, synthesis of hydrogel: 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 dodecylsulfonate and 25 mmol of sodium bromide were weighed and added to 10 mL of deionized water. The mixture was magnetically stirred for 10 min. After all the components were evenly dispersed, nitrogen was bubbled into the system. The bubbles were removed by ultrasonication. The mixture was transferred to an oven for polymerization reaction. The reaction was carried out at 35°C for 10 h to obtain a quaternary ammonium salt hydrogel HMQ-2 with a carbamate structure.

[0091] Example 3

[0092] This embodiment provides a quaternary ammonium salt gel with a carbamate structure, which is specifically prepared by the following steps:

[0093] 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 to carry out a first reaction. The reaction is carried out at 50° C. under condensation reflux for 12 h, and then cooled to room temperature. The product of the first reaction is collected and filtered. The solid is washed with ether and then dried to obtain Quaternary Ammonium Salt Intermediate-3;

[0094] S2, Synthesis of quaternary ammonium salt monomer MQ-3: 40 mmol of quaternary ammonium salt intermediate-3, 40 mmol of isocyanoethyl methacrylate, 0.04 mmol of inhibitor catechol, and 20 μL of catalyst dibutyltin dilaurate were weighed into a round-bottom flask, 100 mL of acetone was added, and a second reaction was carried out at 50° C. for 10 h. The mixture was cooled to room temperature, and the solvent was evaporated for solid-liquid separation to obtain quaternary ammonium salt monomer MQ-3;

[0095] S3, synthesis of hydrogel: 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 were weighed and added to 10 mL of deionized water. The mixture was magnetically stirred for 10 min. After all the components were evenly dispersed, nitrogen was bubbled into the system. The bubbles were removed by ultrasonication. The mixture was transferred to an oven for polymerization reaction. The reaction was carried out at 45°C for 8 h to obtain a quaternary ammonium salt hydrogel HMQ-3 with a carbamate structure.

[0096] Example 4

[0097] This embodiment provides a quaternary ammonium salt gel with a carbamate structure, which is specifically prepared by the following steps:

[0098] 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 to carry out a first reaction. The reaction is carried out at 60° C. under reflux for 6 h, and then cooled to room temperature. The product of the first reaction is collected and filtered. The solid is washed with ether and then dried to obtain Quaternary Ammonium Salt Intermediate-4;

[0099] S2, Synthesis of quaternary ammonium salt monomer MQ-4: 40 mmol of quaternary ammonium salt intermediate-4, 40 mmol of isocyanoethyl methacrylate, 0.04 mmol of inhibitor catechol, and 20 μL of catalyst dibutyltin dilaurate were weighed into a round-bottom flask, 100 mL of acetone was added, and a second reaction was carried out at 55° C. for 12 h. The mixture was cooled to room temperature, and the solvent was evaporated for solid-liquid separation to obtain quaternary ammonium salt monomer MQ-4;

[0100] S3, synthesis of hydrogel: 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 were weighed and added to 10 mL of deionized water. The mixture was magnetically stirred for 10 min. After all the components were evenly dispersed, nitrogen was bubbled into the system. The bubbles were removed by ultrasonication. The mixture was transferred to an oven for polymerization reaction. The reaction was carried out at 50°C for 8 h to obtain a quaternary ammonium salt hydrogel HMQ-4 with a carbamate structure.

[0101] Example 5

[0102] This embodiment provides a quaternary ammonium salt gel with a carbamate structure, which is specifically prepared by the following steps:

[0103] The method of Example 1 was followed, except that "2.5 mmol of quaternary ammonium salt monomer MQ-1 and 17.5 mmol of acrylamide" was changed to "5 mmol of quaternary ammonium salt monomer MQ-1 and 15 mmol of acrylamide" to obtain quaternary ammonium salt hydrogel HMQ-5 with a carbamate structure.

[0104] Example 6

[0105] This embodiment provides a quaternary ammonium salt gel with a carbamate structure, which is specifically prepared by the following steps:

[0106] The method of Example 1 was followed, except that "2.5 mmol of quaternary ammonium salt monomer MQ-1, 17.5 mmol of acrylamide" was changed to "1 mmol of quaternary ammonium salt monomer MQ-1, 19 mmol of acrylamide" to obtain quaternary ammonium salt hydrogel HMQ-6 with a carbamate structure.

[0107] Comparative Example 1

[0108] This comparative example provides a hydrogel, the specific preparation of which includes the following steps:

[0109] Weigh 20 mmol of acrylamide, 0.1 mmol of potassium persulfate and 0.01 mmol of methylene bisacrylamide in 10 mL of deionized water and stir magnetically for 10 min. After the components are evenly dispersed, nitrogen is bubbled into the system and bubbles are removed by ultrasound. The system is transferred to an oven for polymerization reaction and reacted at 35 ° C for 8 h to obtain hydrogel PAM-1.

[0110] Comparative Example 2

[0111] This comparative example provides a hydrogel, the specific preparation of which includes the following steps:

[0112] S1, following the method of step S1 in Example 6;

[0113] S2, synthesis of quaternary ammonium salt monomer MQ-1: 40mmol of quaternary ammonium salt intermediate-1 was weighed in a round-bottom flask and 100mL of tetrahydrofuran was added; 40mmol of methacryloyl chloride and 0.04mmol of inhibitor p-methoxyphenol were weighed in a constant pressure dropping funnel and 100mL of tetrahydrofuran was added; the round-bottom flask was magnetically stirred in an ice bath, and the solution in the constant pressure funnel was continuously added dropwise to the round-bottom flask for the second reaction. The addition time was controlled at 45min. After the addition was completed, the ice bath and magnetic stirring conditions were maintained and the reaction was continued for 6h. After the reaction was completed, the pH of the solution was adjusted to 7 with 0.5mol / L sodium hydroxide solution, tetrahydrofuran was removed by vacuum distillation, and then 100mL of ethyl acetate was added three times for extraction and separation. The oil phase was collected and dried overnight with an appropriate amount of sodium sulfate. The filtrate was filtered and the solvent was removed by vacuum distillation to obtain the quaternary ammonium salt monomer MQ-D2.

[0114] S3, following the method of step S3 in Example 6, except that the "quaternary ammonium salt monomer MQ-1" is replaced with "quaternary ammonium salt monomer MQ-D2" to obtain the quaternary ammonium salt hydrogel HMQ-D2 with a carbamate structure.

[0115] Comparative Example 3

[0116] This comparative example provides a hydrogel, the specific preparation of which includes the following steps:

[0117] The method of Example 6 is followed, except that "N,N-dimethylethanolamine" is replaced by "5-dimethylamino-1-pentanol".

[0118] Comparative Example 4

[0119] This comparative example provides a hydrogel, the specific preparation of which includes the following steps:

[0120] The method of Example 6 was followed, except that "1-bromododecane" was replaced with "1-bromohexane" to obtain quaternary ammonium salt gel HMQ-D4 with a carbamate structure.

[0121] Comparative Example 5

[0122] This comparative example provides a hydrogel, the specific preparation of which includes the following steps:

[0123] The method of Example 6 was followed, except that "1-bromododecane" was replaced with "1-bromoeicosane" to obtain quaternary ammonium salt gel HMQ-D5 with a carbamate structure.

[0124] Test Example 1

[0125] The mechanical strength test method of the hydrogel is as follows: the hydrogel sample is prepared into a specimen with a length of 35mm, a width of 10mm, and a thickness of 1mm for testing. The hydrogel is subjected to a tensile test using a universal tensile testing machine. The test conditions are as follows: temperature of 25°C, gauge length L0 of 20mm, and tensile rate of 100mm / min. The following key data are recorded: maximum tensile force (F max ), displacement at fracture (ΔL), calculate the initial cross-sectional area A (width × thickness) of the sample;

[0126] The specific calculation formula is:

[0127] Elongation at break: ε=ΔL / L0×100%;

[0128] Tensile strength: σ=F max / A;

[0129] The specific test results are shown in Table 1.

[0130] Table 1 Mechanical strength of hydrogels in Examples and Comparative Examples

[0131]

[0132] The tensile strength of the existing hydrophobic association antibacterial hydrogel without a carbamate structure is 307 KPa. The quaternary ammonium hydrogel with a carbamate structure prepared in the present invention has a higher tensile strength.

[0133] Test Example 2

[0134] The hydrogels prepared in the examples and comparative examples were mixed with 1 mL of bacterial suspension (the concentration of Gram-positive Staphylococcus aureus was 1×10 6 CFU / mL, the concentration of Gram-negative Escherichia coli is 1×10 6CFU / mL) were cultured at 37°C for 4 h, and then cultured on LB agar plates (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 three times, and the average value was taken to calculate the bacterial survival rate. The calculation formula is 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.

[0135] Table 2 Bacterial survival rates in Examples and Comparative Examples

[0136]

[0137] The results showed that the quaternary ammonium salt gels with a carbamate structure in the examples had excellent antibacterial properties, especially Example 1, which had the best antibacterial effect, with the bacterial survival rate reduced to 11%.

[0138] Test Example 3

[0139] The hydrogel samples of some embodiments and comparative example 1 were placed in a 96-well microplate culture medium containing cells. The cell type was mouse fibroblasts, and the cell concentration was 5000 cells / well. The cells were cultured in a 37°C, 5% CO2 incubator for 5 days. The cell viability was determined using the CCK-8 method. The specific test method was as follows: 10 μL of CCK-8 reagent was added to each well, and the cells were incubated for 3 hours. The absorbance (OD value) was then measured at a wavelength of 450 nm using a microplate reader. The biocompatibility of the hydrogel was evaluated by calculating the cell viability (%) = (OD value of the experimental group - OD value of the blank group) / OD value of the control group × 100%. If the cell viability of the experimental group is close to or higher than 90%, it indicates that the hydrogel has good biocompatibility; if it is significantly lower than 70%, toxicity may be present. See the specific test results for details. Figure 4 ,like Figure 4 As shown, compared with the comparative example, the cell survival rate in the embodiment is higher, showing good biocompatibility. The hydrogel of the present invention has good safety in biological applications.

[0140] Test Example 4

[0141] At a temperature of 25° C. and a humidity of 50%, cyclic tensile tests at a maximum strain (300%) were performed on Examples 1-6 and Comparative Example 1, and the residual strain changes after different time intervals were recorded.

[0142] The results are as follows Figure 5As shown in (II), the hydrogel samples of Examples 1-6 exhibited lower residual strain in cyclic stretching after a short interval, showing excellent self-recovery performance. In comparison, the residual strain of PAM-1 of Comparative Example 1 was significantly higher, indicating that the hydrogel of the present invention has better adaptability in dynamic applications and improves its application potential in stretching sensors.

[0143] Test Example 5

[0144] Under the conditions of temperature of 25°C and 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 follows: Figure 6 As shown in (II) in the figure, it can be seen that the weight fluctuation of the hydrogel samples of Examples 1-6 is small, indicating that the water retention performance of the hydrogel samples of the examples is significantly better than that of the comparative example 1, and the proportion of the original weight retained is as high as 83%, indicating that the hydrogel of the present invention has excellent water retention capacity in long-term applications. The hydrogel with strong water retention capacity can maintain conductivity and sensitivity during long-term exercise, ensuring that the sensor can accurately capture the motion signal, and has long-term application potential as a motion detection sensor.

[0145] Test Example 6

[0146] The conductivity test of the flexible motion sensor was performed on the hydrogel sample HMQ-2 prepared in Example 2; Figure 7 As shown, after HMQ-2 is connected to the circuit, the LED lamp bead can be lit, indicating that the quaternary ammonium salt gel with a carbamate structure prepared in the present invention has good conductive properties.

[0147] The stability test of the flexible strain sensor was performed on the hydrogel sample HMQ-2 prepared in Example 2; Figure 8 As shown in the figure, under the condition of a stretching range of 50%, after 300 cycles of stretching, the resistance change rate curve range of the hydrogel remains basically unchanged, indicating that the sensor prepared by the present invention has excellent stability and dynamic durability, and has application potential as a motion detection sensor.

[0148] Test Example 7

[0149] 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 meter via copper wires to record the resistance changes of the hydrogel during human motion. Figure 9The researchers also demonstrated the change in the relative resistance (ΔR / R0) of the hydrogel sample during human motion. The experimental results show that when a joint begins to move, the hydrogel's relative resistance increases, reaching a peak when the joint reaches its maximum range of motion. Subsequently, when the joint returns to its initial position, the hydrogel's relative resistance decreases accordingly. Notably, the sensor generates a stable and consistent response signal during repeated movements, demonstrating the hydrogel's excellent strain sensitivity, rapid response, and good repeatability.

[0150] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a quaternary ammonium salt gel containing a carbamate structure, characterized in that: The method comprises 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 gel with a carbamate structure; Wherein, the quaternary ammonium salt monomer is a quaternary ammonium salt containing a carbamate structure, and the structural formula of the quaternary ammonium salt is: ； wherein n is an integer of 9, 11, 13, or 15; m is 2; X is Br; The amide group-containing monomer is selected from at least one of acrylamide, methacrylamide, N-hydroxymethyl acrylamide, N-hydroxymethyl methacrylamide, N-vinyl-N-methylacetamide, N-ethyl acrylamide, and N,N-dimethyl methacrylamide.

2. The preparation method according to claim 1, characterized in that The preparation method of the quaternary ammonium salt containing a carbamate structure comprises the following steps: S1, mixing N,N-dimethylethanolamine, bromoalkane, and solvent A for a first reaction, and performing solid-liquid separation to obtain a quaternary ammonium salt intermediate; S2, mixing the quaternary ammonium salt intermediate, isocyanoethyl methacrylate, a polymerization inhibitor, a catalyst and solvent B to perform a second reaction, and separating the solid and liquid to obtain a quaternary ammonium salt containing a carbamate structure; The brominated alkane is selected from one of 1-bromodecane, 1-bromododecane, 1-bromodedecane, and 1-bromodehexadecane.

3. The preparation method according to claim 2, characterized in that The solvent A and the solvent B are each independently selected from at least one of ethyl acetate, acetone, butanone, cyclohexanone and N,N-dimethylformamide.

4. The preparation method according to claim 2, characterized in that The temperature of the first reaction is 45-60° C., and the time is 6-12 hours.

5. The preparation method according to claim 2, characterized in that The polymerization inhibitor is selected from at least one of phenolic compounds or quinone compounds; And / or, based on the molar amount of isocyanoethyl methacrylate, the amount of the polymerization inhibitor is 0.1-0.3 mol%.

6. The preparation method according to claim 2, characterized in that The catalyst is selected from tin-containing organic salts; And / or, the ratio of isocyanoethyl methacrylate to catalyst is 1 mmol:(0.5-1) μL.

7. The preparation method according to claim 2, characterized in that The temperature of the second reaction is 45-55° C., and the time is 9-12 hours.

8. The preparation method according to claim 5, characterized in that The polymerization inhibitor is selected from at least one of hydroquinone, p-methoxyphenol, p-benzoquinone, and methylhydroquinone.

9. The preparation method according to claim 6, characterized in that The catalyst is selected from at least one of dibutyltin dilaurate and stannous octoate.

10. The preparation method according to claim 1, characterized in that The molar ratio of the quaternary ammonium salt monomer to the amide group-containing monomer is 1:3-19.

11. The preparation method according to claim 1, characterized in that The amount of the initiator used is 0.05-0.1 mol % based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer.

12. The preparation method according to claim 1, characterized in that The amount of the cross-linking agent used is 0.03-0.2 mol % based on the total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer.

13. The preparation method according to claim 1, characterized in that Based on the mass of the mixed solution, the concentration of the emulsifier is 60-100 g / L.

14. The preparation method according to claim 1, characterized in that Based on the mass of the mixed solution, the concentration of metal ions in the inorganic salt is 1-3 mol / L.

15. The preparation method according to claim 1, characterized in that The total molar amount of the quaternary ammonium salt monomer and the amide group-containing monomer and the amount of water are in a ratio of (1.50-3.00) mmol:1 mL.

16. The preparation method according to claim 1, characterized in that The polymerization reaction temperature is 35-50° C. and the reaction time is 8-12 hours.

17. The preparation method according to claim 1, characterized in that The initiator is selected from persulfates.

18. The preparation method according to claim 1, characterized in that The cross-linking agent is methylene bisacrylamide.

19. The preparation method according to claim 1, characterized in that The emulsifier is selected from sulfonates.

20. The preparation method according to claim 1, characterized in that The inorganic salt is selected from at least one of chloride salts and bromide salts.

21. A quaternary ammonium salt gel containing a carbamate structure obtained by the preparation method according to any one of claims 1 to 20.

22. An antibacterial material, characterized in that: The antibacterial material comprises the quaternary ammonium salt gel containing a carbamate structure as claimed in claim 21.

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