Negative ion sensor based on cizs quantum dots cotton fabric, preparation method and application thereof

Abstract

The application discloses a kind of based on CIZS quantum dot cotton fabric negative ion sensor and preparation method and application, including the following steps, (1) preparation Cu-In-Zn-S quantum dot;(2) ligand exchange;(3) cotton fabric is desized, cation modification treatment: natural cotton fabric is desized, and the cotton fabric after desizing is cation modification treatment;(4) cotton fabric coupling treatment;(5) quantum dot is adsorbed on the cotton fabric that is coupled by impregnation method with chitosan, and by with quantum dot surface small molecule functional ligand reaction, make quantum dot anchor on the surface of cotton fabric;With 3-mercaptopropionic acid as short chain ligand, make quantum dot can be dispersed in aqueous solution, small molecule functional ligand is with the reactivity of quantum dot and coupling resin to adjust.The natural cotton fabric is selected as carrier, adds PER and chitosan, adds Cu-In-Zn-S quantum dot and makes it evenly distributed on the surface of cotton fiber, successfully realizes the combination of quantum dot and flexible fabric base material.

Description

Technical Field

[0001] This invention relates to the field of novel nanocomposite materials technology, and specifically to a negative ion sensor based on CIZS quantum dot cotton fabric, its preparation method, and its application. Background Technology

[0002] Quantum dots (QDs) are inorganic semiconductor luminescent nanocrystals with physical diameters ranging from 1 to 10 nm, whose particle diameters are smaller than or close to the exciton Bohr radius. Quantum dots possess excellent photophysical properties, such as high fluorescence quantum yield, unique size-controlled fluorescence and resistance to photobleaching, wide absorption and narrow emission, and advantages including a wide color gamut, complete chromatogram, and high intensity. Although there are many fundamental physical and chemical discoveries to be made in nanofilms, quantum dots can be used for fluorescence, photonics, and electrochemical applications. The emission wavelength of quantum dots can be tuned by both composition and size; different excitation wavelengths result in different emission wavelengths. Based on the high photothermal stability, good solution handling, and controllable surface chemistry of quantum dots, researchers believe that quantum dots, as excellent luminescent materials, can be widely used in quantum dot detection, biosensors, digital communications, optoelectronics, catalysis, sensor problems, light-emitting diodes (LEDs), white LEDs, solar cells, photodetectors, and other fields.

[0003] CuInZnS quantum dots, as a novel fluorescent probe, possess excellent optical properties, such as high fluorescence intensity and tunable emission spectra. They exhibit specific responses to certain negatively charged groups, enabling highly sensitive and selective detection. Compared to traditional Cd-based quantum dots, CuInZnS quantum dots do not contain heavy metals (such as Cd and Pb), exhibiting lower toxicity and better biocompatibility. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a CIZS quantum dot cotton fabric sensor, its preparation method, and its application.

[0005] The present invention adopts the following technical solution:

[0006] A method for fabricating a negative ion sensor based on CIZS quantum dot cotton fabric includes the following steps:

[0007] (1) Preparation of Cu-In-Zn-S quantum dots;

[0008] (2) Ligand exchange: The original long-chain ligands of the quantum dots are replaced with small molecule functional ligands, which have amphiphilic characteristics with both quantum dots and media;

[0009] (3) Desizing and cationic modification treatment of cotton fabrics: Desizing treatment of natural cotton fabrics and cationic modification treatment of desizing cotton fabrics.

[0010] (4) Cotton fabric coupling treatment: Cotton fabric is treated with chitosan coupling to obtain cotton fabric treated with chitosan coupling.

[0011] (5) Quantum dots are adsorbed onto cotton fabrics that have been coupled with chitosan by impregnation, and the quantum dots are anchored on the surface of the cotton fabrics by reacting with small molecule functional ligands on the surface of the quantum dots.

[0012] The preparation method described above, in step (1), the preparation method of the Cu-In-Zn-S quantum dots is as follows:

[0013] (1) Dissolve indium acetate in the solvent octadecene and the ligand oleylamine by heating. After complete dissolution, remove oxygen to obtain a mixed solution of indium.

[0014] (2) Dissolve sulfur completely in octadecene, add the dissolved sulfur mixture to the cooled indium mixture obtained in step (1), mix to remove oxygen, and heat to raise the temperature;

[0015] (3) When the mixed solution obtained in step (2) is heated to a certain temperature, the reaction is maintained in a nitrogen atmosphere for a period of time, the dissolved copper mixed solution is added, and the temperature is lowered after the reaction is carried out for a certain period of time.

[0016] (4) At a certain temperature, add the dissolved zinc mixed solution, react for a period of time and then heat it. When the target temperature is reached, stop heating. Keep the mixed solution at the target temperature for a period of time. After the reaction is completed, cool it down to room temperature, add excess isopropanol and centrifuge to obtain the solution.

[0017] In the preparation method described above, in step (2), an alkaline solution of 3-mercaptopropionic acid-methanol is prepared by adding 3-mercaptopropionic acid to the methanol solution and adding sodium hydroxide solution to adjust the pH value to 10; the CuInZnS quantum dot solution and the alkaline solution of 3-mercaptopropionic acid-methanol are mixed and stirred thoroughly to ensure that the CuInZnS quantum dot solution and the alkaline solution of 3-mercaptopropionic acid-methanol are uniformly mixed; the solution is placed on a magnetic stirrer and stirred vigorously. Specifically: Add 160-640 μL of 3-mercaptopropionic acid to 2-4 mL of methanol solution, and adjust the pH to 10 by adding 230 μL of 30% sodium hydroxide solution. Mix the CuInZnS quantum dot solution with the alkaline 3-mercaptopropionic acid-methanol solution, and stir the mixture thoroughly to ensure uniform mixing. Place the solution on a magnetic stirrer and stir vigorously at 800 rpm for 30-90 minutes. Add excess isopropanol, centrifuge, remove the supernatant, and then add 5 mL of methanol again and centrifuge twice.

[0018] In the preparation method described above, step (3) involves the following steps: Add an appropriate amount of sodium hydroxide to distilled water to prepare a sodium hydroxide aqueous solution, and add JFC solution dropwise, stirring until homogeneous. Immerse the cotton fabric in the above mixture, heat to boiling, and after treatment, remove the cotton fabric and wash it sequentially with hot water and warm water, finally rinsing it with room temperature water to neutralize its pH. Dry the desized pure cotton fabric for later use. Specifically, prepare a 10 g / L sodium hydroxide aqueous solution, add 2-4 drops of JFC solution (1 g / L), and stir until homogeneous. Immerse the cotton fabric in the above mixture, heat to boiling, and continue boiling for 30 minutes. After treatment, remove the cotton fabric, rinse it, and neutralize its pH. Dry the pretreated pure cotton fabric in an 80℃ oven for later use.

[0019] In the preparation method described above, step (3) involves the following cationic modification treatment: A (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) solution is prepared as a cationic modifier and heated. The desized cotton fabric is then immersed in this solution at a bath ratio of 1:20. After immersion, sodium hydroxide solution is added, and the solution is maintained under these conditions for a certain period of time. After treatment, the cotton fabric is removed and washed in cold water until neutral. Alternatively, 20 ml of a 60 g / L (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) solution is prepared as a cationic modifier and heated to 80°C. The desized cotton fabric is then immersed in this solution for 10 minutes, followed by the addition of 20 ml of a 15 g / L sodium hydroxide solution, and the solution is maintained under these conditions for 40 minutes. After treatment, the cotton fabric is removed and washed in cold water until neutral.

[0020] In the preparation method described above, step (4) involves the following steps: preparing a pentaerythritol (PER) solution and adding JFC penetrant. After thorough stirring, the solution is placed in a cationic modified cotton fabric and heated in an oil bath at 80°C for 1-2 hours. The fabric is then removed and dried. An acetate-sodium acetate (HAc-NaAc) buffer solution is prepared, and the chitosan coupling agent is dissolved in the buffer solution. A chitosan solution with a concentration of 0.1-10 g / L is prepared, and 1-50 drops of JFC penetrant are added to it. The cotton fabric is then immersed in the solution and heated in an oil bath at 70°C for 1-1.5 hours. The fabric is then removed, the water is pressed out, and the fabric is dried. Finally, it is dried in an oven at 165-180°C for two minutes to obtain the chitosan-coupled cotton fabric. Specifically: Prepare 20 mL of 15 g / L pentaerythritol (PER), add 4 drops of 1 g / L JFC-type penetrant, stir thoroughly, and set aside as a crosslinking agent solution; place the cationic-treated cotton fabric in this crosslinking agent solution, heat in an oil bath at 80°C for 1-2 hours, remove and dry, then dry in an oven at 120°C-210°C for 1-30 minutes; prepare 2000 mL of 0.2 mol / L acetate-sodium acetate (HAc-NaAc) buffer solution, dissolve chitosan in the buffer solution to prepare 2000 mL of 0.1-10 g / L chitosan solution, add 1-10 drops of JFC penetrant, immerse the cotton fabric in the solution, heat in an oil bath at 80°C for 1-1.5 hours, remove, press out the water with a fabric press, dry, and then heat at 165-180°C. Dry in an oven for two minutes to obtain a cotton fabric treated with chitosan.

[0021] In the preparation method described above, step (5) involves dissolving ligand-exchanged CIZS quantum dots in water, adding a small amount of JFC penetrant, and then placing the treated cotton fabric in the solution and reacting at 60-70°C for 2-3 hours. After the reaction, the cotton fabric is removed from the beaker and leveled using a rolling mill with a pressure of 0.1-1 MPa and a speed of 1-30 m / min. Then, the cotton fabric is dried at 70-80°C for 10 min and baked at 165-180°C for 3 min to obtain CIZS quantum dot fluorescent cotton fabric. Specifically, 0.3 g of ligand-exchanged CIZS quantum dots are dissolved in 10 mL of water, 4 drops of JFC penetrant are added, and the treated cotton fabric is placed in the solution and reacted at 80°C for 2 hours. After the reaction, the cotton fabric is removed from the beaker and leveled using a pneumatic small rolling mill with a pressure of 0.2 MPa and a speed of 3 m / min. Then, fluorescent cotton fabric containing CIZS quantum dots was obtained by drying the cotton fabric at 80°C for 10 min and baking it at 180°C for 3 min.

[0022] CIZS quantum dot fluorescent cotton fabric prepared according to any of the preparation methods described.

[0023] According to the application of the CIZS quantum dot fluorescent cotton fabric in the detection of negative ions, the negative ions include F - OH - or Cl - 。

[0024] The present invention has the following technical effects:

[0025] 1. Uniformly sized and stably luminescent Cu-In-Zn-S quantum dots modified with oleylamine ligands were prepared. A two-phase ligand exchange technique was employed, using 3-mercaptopropionic acid as a short-chain ligand to disperse the quantum dots in aqueous solution. Small-molecule functional ligands were used to modulate the reactivity between the quantum dots and the coupling resin. Natural cotton fabric was selected as the carrier, and PER and chitosan were added. Cu-In-Zn-S quantum dots were then added and uniformly distributed on the cotton fiber surface, successfully achieving the bonding of quantum dots to a flexible fabric substrate. The prepared wearable luminescent cotton fabric emitted orange-red fluorescence with a fluorescence lifetime of 5.9 microseconds. Furthermore, the FCS maintained good fluorescence performance after 50 washing tests and 1800 bending tests, demonstrating excellent durability and practical application value.

[0026] 2. The luminescent cotton fabric prepared by this invention is a sensitive and safe novel wearable sensing material. FCS can sense negatively charged groups (OH⁻, F⁻, Cl⁻) through changes in fluorescence intensity, and the changes in fluorescence intensity exhibit a certain functional law, which helps to qualitatively and quantitatively sense negatively charged groups through changes in fluorescence intensity. Attached Figure Description

[0027] Figure 1 (a) Transmission electron microscope image and (b) electron diffraction pattern of CuInZnS quantum dots used in the material preparation stage of the present invention in Example 1;

[0028] Figure 2 The fluorescence emission spectra of CuInZnS quantum dots before and after ligand exchange used in the material preparation stage of this invention in Example 1;

[0029] Figure 3 The fluorescence lifetime spectra of CuInZnS quantum dots after ligand exchange in Examples 1-3;

[0030] Figure 4 Fluorescence emission spectra of CuInZnS quantum dots and CuInZnS quantum dot fluorescent fabrics;

[0031] Figure 5Photographs of (a) natural cotton fabric (left) and fluorescent cotton fabric (right) under sunlight, and (b) natural cotton fabric (left) and fluorescent cotton fabric (right) under 365nm ultraviolet light.

[0032] Figure 6 Fitting plot of F0 / F-negative group concentration trend and corresponding formula for the effect of different concentrations of different negatively charged groups on the fluorescence change of fluorescent cotton fabric;

[0033] Figure 7 Fluorescence emission spectra of fluorescent cotton fabrics after different folding times;

[0034] Figure 8 Fluorescence emission spectra of fluorescent cotton fabrics after different washing cycles; Detailed Implementation

[0035] The present invention will be described in detail below with reference to specific embodiments. Example 1

[0036] Take 0.234g of indium acetate powder, 0.0128g of sulfur powder, 18ml of 1-octadecene and 4ml of oleic acid into a three-necked flask, heat at 100℃ under vacuum for 10min to ensure complete dissolution of the drugs, then continue heating to 120℃ under a nitrogen atmosphere and inject a solution of cuprous iodide in 1-dodecylthiol (DDT), then continue heating to 160℃ and hold for 5min, and after naturally cooling to 100℃, inject a mixed solution of zinc oxide in 2-ethylhexanoic acid and 1-octadecene. After holding at this temperature for 10 minutes, the temperature was increased to 240℃ at a rate of 10℃ / min and held for another 10 minutes. Then, a mixed solution of thiourea and zinc oxide was injected, and the mixture was held for another 10 minutes. After cooling naturally to room temperature, 20 ml of methanol solution was added to precipitate the quantum dots. The precipitate was then transferred to a 10 ml centrifuge tube and centrifuged at 12000 rpm for 10 minutes. After discarding the supernatant, 3 ml of trichloroethylene was added to dissolve the quantum dots. Then, 7 ml of methanol solution was added to precipitate the quantum dots. The mixture was centrifuged at 12000 rpm for 10 minutes. This process was repeated three times. The mixture was then dried in a vacuum drying oven at 40℃ for 8 hours to obtain quantum dot powder.

[0037] like Figure 1 As shown, observations using a TEM transmission electron microscope revealed that the quantum dot has a uniform size and good morphology.

[0038] The obtained CuInZnS QDs were dried in a vacuum drying oven. 0.6g of CuInZnS QDs powder was weighed and added to 20mL of dichloromethane and mixed with a magnetic stirrer.

[0039] To prepare an alkaline solution of 3-mercaptopropionic acid and methanol, add 160 μL of 3-mercaptopropionic acid to 2 mL of methanol solution, and then add 2 drops of 30% sodium hydroxide solution to adjust the pH to 10.

[0040] A CuInZnS quantum dot solution and an alkaline solution of 3-mercaptopropionic acid-methanol were mixed, and the prepared mixture was stirred thoroughly to ensure homogeneity. The solution was then placed on a magnetic stirrer at 800 rpm for 30 minutes of vigorous stirring. After vigorous stirring, the mixture no longer showed obvious stratification and exhibited an unstable suspension state. Next, excess isopropanol solution was added to the suspension and transferred to centrifuge tubes. The centrifuge tubes were placed in a high-speed centrifuge at 10,000 rpm for 10 minutes. After centrifugation, the precipitate was removed from the centrifuge tube wall and initially dissolved with 20 mL of methanol. The completely dissolved precipitate was then further dissolved with 20 mL of isopropanol to form a new suspension for further washing. This washing process was repeated three times, and the precipitate was then dried in a vacuum drying oven.

[0041] like Figure 2 As shown, the fluorescence intensity of the quantum dots decreases slightly after ligand exchange, but they still exhibit excellent luminescence properties. Figure 3 As shown, the fluorescence lifetime of the quantum dot after ligand exchange is 5.9 μs.

[0042] Desizing treatment of cotton fabrics: Add an appropriate amount of sodium hydroxide to distilled water to prepare 50 mL of a 10 g / L sodium hydroxide aqueous solution. Next, add 2 drops of JFC penetrant solution (1 g / L) and stir well. Immerse a 5 cm x 5 cm piece of cotton fabric in the above mixture (liquor ratio: 1:50), heat to boiling, and continue boiling for 30 minutes. After treatment, rinse to neutralize the pH. Place the desizing pure cotton fabric in an 80℃ oven to dry, and set aside for later use.

[0043] Cationic modification treatment: Prepare 20 mL of a 60 g / L (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) solution and heat to 80 °C as the cationic modifier. Immerse the desized cotton fabric in this solution. After immersion for 10 minutes, add 20 mL of a 15 g / L sodium hydroxide solution and maintain this condition for 40 minutes. After treatment, remove the cotton fabric and wash it in cold water until neutral.

[0044] Prepare 20 mL of a 15 g / L pentaerythritol (PER) solution and add 2 drops of 1 g / L JFC type penetrant. Stir thoroughly and immerse the cotton fabric in a beaker containing the pentaerythritol and JFC mixed solution (liquor ratio 1:20). Heat the beaker in an oil bath at 80°C for 2 hours, remove and dry, then bake in an oven at 160°C for 2 minutes to obtain the surface-modified pure cotton fabric.

[0045] Prepare 2000 ml of 0.2 mol / L acetate-sodium acetate (HAc-NaAc) buffer solution. Dissolve chitosan in the buffer solution to prepare 2000 ml of 1 g / L chitosan solution. Add 2 drops of JFC penetrant to the solution. Immerse the cotton fabric in the solution and heat it in an oil bath at 70°C for 1.5 hours. After removing it, press out the water with a fabric press and dry it. Then dry it in an oven at 180°C for two minutes to obtain cotton fabric treated with the coupling agent chitosan.

[0046] 0.3 g of CIZS quantum dots, after ligand exchange, were dissolved in 10 mL of water and poured into a beaker. Two drops of JFC penetrant were added to the beaker, and the cotton fabric treated with the coupling agent chitosan was placed inside. The reaction was carried out at 70 °C for 3 hours. After the reaction, the cotton fabric was removed from the beaker and leveled using a small pneumatic mill with a pressure of 0.2 MPa and a speed of 3 m / min. Then, the cotton fabric was dried at 70 °C for 10 min and baked at 160 °C for 3 min to obtain fluorescent cotton fabric containing CIZS quantum dots.

[0047] like Figure 4 The quantum dots shown endow fluorescent cotton fabrics with excellent photophysical properties. For example... Figure 5 As shown, fluorescent cotton fabric emits a bright orange-red fluorescence under ultraviolet light.

[0048] To ensure that the CIZS quantum dot-grafted cotton fabric not only possesses excellent fluorescence properties but also outstanding durability, multiple folding experiments were conducted, simulating the folding motion of an elbow during everyday wear. After the experiments, the fluorescence intensity at the folds was measured to assess the change in fluorescence performance during the folding process. The experimental results are as follows: Figure 7 As shown, although the fluorescence properties decreased slightly during 0-1800 folds, the overall decrease was minimal, and the fabric still exhibited good fluorescence. Experimental results indicate that fluorescent cotton fabric retains its luminescent properties after multiple folds and demonstrates good durability. The changes in fluorescence intensity of fluorescent cotton fabric after multiple washes were investigated.

[0049] Figure 8The changes in the fluorescence spectrum of fluorescent cotton fabric after multiple washes were demonstrated. The results showed that after 30 washes, the fluorescence intensity of the fabric slightly decreased, but then remained relatively constant. This phenomenon may be due to the fact that some quantum dots on the fabric surface did not fully participate in the reaction with the cotton, resulting in a certain amount of unreacted CIZS quantum dots (QDs). In the initial stage of washing, these loosely bound excess CIZS QDs were washed away, leading to a slight decrease in fluorescence intensity. During the washing process, the excess quantum dots were washed away, and the reacting CIZS quantum dots were covalently bonded to the cotton fibers, exhibiting stable fluorescence properties. Therefore, using covalent bonds to fix CIZS quantum dots onto cotton fabric can achieve better wash resistance.

[0050] Add an appropriate amount of sodium fluoride to deionized water to prepare a 10 mL 0.1 mol / L sodium fluoride solution. Cut the prepared fluorescent fabric into 1.5 cm × 1.5 cm squares, then use a pipette to drop the sodium fluoride solution onto the fluorescent fabric. After drying, test the change in fluorescence intensity using a full-spectrum microspectrometry instrument. Compare the relative fluorescence intensity of the fluorescent fabric with F... - The quenching relationship between concentrations was fitted, and the results are as follows: Figure 6 As shown in (a1). Within the concentration range of 0-8 μmol, the fitted equation and parameters are as follows: Figure 6 As shown in (a2). Example 2

[0051] The prepared CuInZnS quantum dot (QDs) were dried in a vacuum drying oven. 0.6 g of the powder was weighed and added to 20 mL of dichloromethane, and mixed using a magnetic stirrer. An alkaline solution of 3-mercaptopropionic acid-methanol was prepared by adding 320 μL of 3-mercaptopropionic acid to 3 mL of methanol solution, and adjusting the pH to 10 by adding 3 drops of 30% sodium hydroxide solution. The CuInZnS quantum dot solution and the alkaline 3-mercaptopropionic acid-methanol solution were mixed, and the prepared mixture was stirred thoroughly. The solution was then placed on a magnetic stirrer and stirred vigorously at 800 rpm for 60 minutes. Next, excess isopropanol solution was added to the suspension, and the mixture was transferred to a centrifuge tube and centrifuged. Figure 3 As shown, the fluorescence lifetime of the quantum dot after ligand exchange is 5.8 μs.

[0052] Desizing treatment of cotton fabrics: Add an appropriate amount of sodium hydroxide to distilled water to prepare 50 mL of a 10 g / L sodium hydroxide aqueous solution. Then, add 3 drops of JFC solution (1 g / L) and stir well. Immerse a 5 cm * 5 cm cotton fabric in the above mixture (liquor ratio: 1:50), heat to boiling, and continue boiling for 60 minutes. Then wash until the pH is neutral. Place the pretreated pure cotton fabric in an 80℃ oven to dry.

[0053] Cationic modification treatment: Prepare 20 ml of a 60 g / L (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) solution and heat to 70°C. Immerse the desized cotton fabric in this solution. After soaking for 10 minutes, add 20 ml of a 15 g / L sodium hydroxide solution and maintain this condition for 40 minutes. After treatment, remove the cotton fabric and wash it in cold water until neutral.

[0054] Prepare 20 mL of 15 g / L pentaerythritol (PER), add 3 drops of 1 g / L JFC-type penetrant, stir thoroughly, and place in a beaker as a crosslinking agent. Place the cationic-treated cotton fabric in this beaker, heat the beaker in an oil bath at 80°C for 2 hours, remove and dry, and then dry in an oven at 170°C for 2 minutes to obtain surface-modified pure cotton fabric.

[0055] Prepare 2000 ml of 0.2 mol / L acetate-sodium acetate (HAc-NaAc) buffer solution. Dissolve chitosan in the buffer solution to prepare 2000 ml of 1 g / L chitosan solution. Add 3 drops of JFC penetrant to the solution. Immerse cotton fabric in the solution and heat in an oil bath at 70°C for 1.5 hours. Remove the fabric, press out the water with a fabric press, dry it, and then dry it in an oven at 170°C for two minutes to obtain cotton fabric treated with chitosan coupling.

[0056] After ligand exchange, 0.3 g of CIZS quantum dots were dissolved in 10 mL of water and poured into a beaker. Three drops of JFC penetrant were added to the beaker, and the treated cotton fabric was placed inside and reacted at 70 °C for 2 hours. After the reaction, the cotton fabric was removed from the beaker and smoothed using a small pneumatic mill with a pressure of 0.2 MPa and a speed of 3 m / min. Then, fluorescent cotton fabric containing CIZS quantum dots was obtained by drying the cotton fabric at 70 °C for 10 min and baking it at 170 °C for 3 min.

[0057] Add an appropriate amount of sodium hydroxide to deionized water to prepare 10 mL of a 0.1-0.8 mol / L sodium hydroxide solution. Cut the prepared fluorescent fabric into 1.5 cm × 1.5 cm squares, then use a pipette to drop the sodium hydroxide solution onto the fluorescent fabric. After drying, test the change in fluorescence intensity using a full-spectrum microspectrometry instrument. Relate the relative fluorescence intensity of the fluorescent fabric to the sodium hydroxide solution. - The quenching relationship between concentrations was fitted, and the results are as follows: Figure 6 As shown in (b1). Within the concentration range of 0-8 μmol, the fitted equation and parameters are as follows: Figure 6 As shown in (b2). Example 3

[0058] The prepared CuInZnS quantum dot (QDs) were dried in a vacuum drying oven. 0.6 g of the powder was weighed and added to 20 mL of dichloromethane, and mixed using a magnetic stirrer. An alkaline solution of 3-mercaptopropionic acid-methanol was prepared by adding 640 μL of 3-mercaptopropionic acid to 4 mL of methanol solution and adjusting the pH to 10 with 5 drops of 30% sodium hydroxide solution. The CuInZnS quantum dot solution and the alkaline 3-mercaptopropionic acid-methanol solution were mixed, and the prepared mixture was stirred thoroughly. The solution was then placed on a magnetic stirrer and stirred vigorously at 800 rpm for 90 minutes. Next, excess isopropanol solution was added to the suspension, and the mixture was transferred to a centrifuge tube and centrifuged. Figure 3 As shown, the fluorescence lifetime of the quantum dot after ligand exchange is 5.7 μs.

[0059] Desizing treatment of cotton fabrics: Add an appropriate amount of sodium hydroxide to distilled water to prepare 50 mL of a 10 g / L sodium hydroxide aqueous solution. Next, add 4 JFC solution (1 g / L) dropwise and stir until homogeneous. Immerse a 5 cm x 5 cm cotton fabric in the above mixture and heat to boiling, continuing to boil for 90 minutes. Then wash until the pH is neutral. Place the pretreated pure cotton fabric in an 80°C oven to dry.

[0060] Cationic modification treatment: Prepare 20 ml of a 60 g / L (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) solution and heat to 80°C. Immerse the desized cotton fabric in this solution. After soaking for 10 minutes, add 20 ml of a 15 g / L sodium hydroxide solution and maintain this condition for 40 minutes. After treatment, remove the cotton fabric and wash it in cold water until neutral.

[0061] Prepare 20 mL of 15 g / L pentaerythritol (PER), add 4 drops of 1 g / L JFC-type penetrant, stir thoroughly, and place in a beaker for later use. Place the cationic-treated cotton fabric in this beaker, heat the beaker in an oil bath at 80°C for 2 hours, remove and dry, then dry in an oven at 180°C for 2 minutes to obtain surface-modified pure cotton fabric. Prepare 2000 mL of 0.2 mol / L acetate-sodium acetate (HAc-NaAc) buffer solution, dissolve chitosan in the buffer solution to prepare 2000 mL of 1 g / L chitosan solution, add 4 drops of JFC penetrant, immerse the cotton fabric in the solution, heat in an oil bath at 80°C for 2 hours, remove, press out the water with a fabric press, dry, and then dry in an oven at 180°C for 2 minutes to obtain chitosan-coupled cotton fabric. After ligand exchange, 0.3 g of CIZS quantum dots were dissolved in 10 mL of water and poured into a beaker. Four drops of JFC penetrant were added to the beaker, and the treated cotton fabric was placed inside and reacted at 80 °C for 2 hours. After the reaction, the cotton fabric was removed from the beaker and smoothed using a small pneumatic mill with a pressure of 0.2 MPa and a speed of 3 m / min. Then, fluorescent cotton fabric containing CIZS quantum dots was obtained by drying the cotton fabric at 80 °C for 10 min and baking it at 180 °C for 3 min.

[0062] Add an appropriate amount of sodium chloride to deionized water to prepare 10 mL of a 0.1-0.8 mol / L sodium chloride solution. Cut the prepared fluorescent fabric into 1.5 cm × 1.5 cm squares, then use a pipette to drop the sodium chloride solution onto the fluorescent fabric. After drying, use a full-spectrum microspectrometry instrument to test the change in fluorescence intensity. Compare the relative fluorescence intensity of the fluorescent fabric with that of the sodium chloride solution. - The quenching relationship between concentrations was fitted, and the results are as follows: Figure 6 As shown in (C1). Within the concentration range of 0-8 μmol, the fitted equation and parameters are as follows: Figure 6 As shown in (C2).

[0063] like Figure 6 As shown, Fo is the photoluminescence intensity (PL) of the fluorescent cotton fabric at a specified emission wavelength, and F is the PL intensity of the fluorescent cotton fabric in contact with the solution of negatively charged groups. OH - and F - The fluorescence intensity quenching of fluorescent cotton fabrics follows a nonlinear functional relationship, with fitting variances of R² = 0.9933 and R² = 0.9995, respectively. - The effect of fluorescence intensity on the relative fluorescence intensity of fluorescent cotton fabric follows a certain linear functional relationship, with a fitting variance of R² = 0.9810. The quenching characteristic curve shows that OH... - It exhibits the highest quenching effect and best sensitivity on fluorescent cotton fabrics.- Next.

[0064] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a negative ion sensor based on CIZS quantum dot cotton fabric, characterized in that, Includes the following steps: (1) Preparation of Cu-In-Zn-S quantum dots; (2) Ligand exchange: The original long-chain ligands of the quantum dots are replaced with small molecule functional ligands, which have amphiphilic characteristics with both quantum dots and media; Specifically: Prepare an alkaline solution of 3-mercaptopropionic acid-methanol by adding 3-mercaptopropionic acid to the methanol solution and adjusting the pH to 10 by adding sodium hydroxide solution dropwise; mix the CuInZnS quantum dot solution and the alkaline solution of 3-mercaptopropionic acid-methanol, and stir the prepared mixture thoroughly to ensure that the CuInZnS quantum dot solution and the alkaline solution of 3-mercaptopropionic acid-methanol are uniformly mixed; place the solution on a magnetic stirrer and stir vigorously. (3) Desizing and cationic modification treatment of cotton fabrics: Desizing treatment of natural cotton fabrics and cationic modification treatment of desizing cotton fabrics. (4) Cotton fabric coupling treatment: Prepare pentaerythritol solution and add JFC penetrant. After stirring thoroughly, put the cationic modified cotton fabric into the solution and heat it in an oil bath at 80 degrees Celsius for 1-2 hours. Take it out and dry it. Prepare an acetate-sodium acetate buffer solution and dissolve the coupling agent chitosan in the buffer solution to prepare a chitosan solution with a concentration of 0.1-10 g / L. Add 1-50 drops of JFC penetrant to the solution and immerse the cotton fabric in the solution. Heat it in an oil bath at 70 degrees Celsius for 1-1.5 hours. Take it out, press out the water, dry it, and then dry it in an oven at 165-180 °C for two minutes to obtain the cotton fabric treated with chitosan coupling. (5) The quantum dots after ligand exchange are adsorbed onto the cotton fabric treated with chitosan by impregnation, and the quantum dots are anchored on the surface of the cotton fabric by reacting with the small molecule functional ligands on the surface of the quantum dots.

2. The preparation method according to claim 1, characterized in that, In step (1), the preparation method of the Cu-In-Zn-S quantum dots is as follows: Take 0.234 g of indium acetate powder, 0.0128 g of sulfur powder, 18 ml of 1-octadecene, and 4 ml of oleic acid in a three-necked flask. Heat under vacuum at 100 °C for 10 min to ensure complete dissolution of the chemicals. Then, under a nitrogen atmosphere, continue heating to 120 °C and inject a solution of cuprous iodide in 1-dodecylthiol. Continue heating to 160 °C and hold for 5 min. After natural cooling to 100 °C, inject a mixed solution of zinc oxide in 2-ethylhexanoic acid and 1-octadecene. Hold for 10 min, then heat to 240 °C at a rate of 10 °C / min and hold for 10 min. Finally, inject thiourea and... The zinc oxide mixed solution was kept at a temperature of 10 min and then naturally cooled to room temperature. 20 ml of methanol solution was added to precipitate the quantum dots, and the precipitate was poured into a 10 ml centrifuge tube. The tube was centrifuged at 12000 r / min for 10 min. After discarding the supernatant, 3 ml of trichloroethylene was added to dissolve the quantum dots, and then 7 ml of methanol solution was added to precipitate the quantum dots. The tube was centrifuged at 12000 r / min for 10 min. This process was repeated three times. The tube was then dried in a vacuum drying oven at 40℃ for 8 h to obtain quantum dot powder.

3. The preparation method according to claim 1, characterized in that, In step (3), the desizing process is as follows: add an appropriate amount of sodium hydroxide to distilled water to prepare a sodium hydroxide aqueous solution, and add JFC solution dropwise and stir evenly; immerse the cotton fabric in the above mixture, heat to boiling, and after the treatment is completed, take out the cotton fabric, wash it with hot water and warm water in sequence, and finally rinse it with room temperature water to make its pH value neutral; place the desized pure cotton fabric in an 80℃ oven to dry and wait for use.

4. The preparation method according to claim 1, characterized in that, In step (3), the cationic modification treatment is as follows: prepare a (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) solution as a cationic modifier, heat it, and soak the desized cotton fabric in this solution; after soaking, add sodium hydroxide solution and maintain it under these conditions for a certain period of time; After processing, remove the cotton fabric and wash it in cold water until it is neutral.

5. The preparation method according to claim 1, characterized in that, In step (5), CIZS quantum dots after ligand exchange are dissolved in water, and a small amount of JFC penetrant is added. The treated cotton fabric is then placed in the solution and reacted at 60-70℃ for 2-3 hours. After the reaction, the cotton fabric is removed from the beaker and leveled using a rolling mill with a pressure of 0.1-1 MPa and a speed of 1-30 m / min. Then, CIZS quantum dot fluorescent cotton fabric is obtained by drying the cotton fabric at 70-80℃ for 10 min and baking it at 165-180℃ for 3 min.

6. CIZS quantum dot fluorescent cotton fabric prepared by any one of the preparation methods according to claims 1-5.

7. The application of the CIZS quantum dot fluorescent cotton fabric according to claim 6 in the detection of negative ions, wherein the negative ions include F - OH - or Cl - .

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