Conjugated polymer precursor and preparation thereof, conjugated polymer and preparation and application thereof, hydrogel film fluorescence sensor and preparation and application thereof, and biodegradation method

Abstract

The present invention provides a conjugated polymer precursor and its preparation, a conjugated polymer and its preparation and application, a hydrogel thin film fluorescence sensor and its preparation and application, and a biodegradation method, belonging to the technical field of thin film fluorescence sensors. The conjugated polymer provided by the present invention not only has a unique "molecular line effect" that can amplify fluorescence signals and improve quantum yield, but also can specifically identify chromate ions. The present invention uses 3D printing to prepare the conjugated polymer with sodium alginate and polyvinyl alcohol into a thin film fluorescence sensor with the conjugated polymer as a sensing unit and sodium alginate and polyvinyl alcohol as a gel base. The hydrogel thin film fluorescence sensor of the present invention has both good sensing performance and biodegradation characteristics, can be recycled and reused, has controllable shape, low cost, is environmentally friendly, and has strong adaptability to various detection environments, solving the problem that traditional fluorescence sensors are difficult to degrade and have high production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film fluorescence sensors, in particular to a conjugated polymer precursor and its preparation, a conjugated polymer and its preparation and application, a hydrogel thin film fluorescence sensor and its preparation and application, and a biodegradation method. Background Art

[0002] With the rapid advancement of industrialization and the widespread use of agricultural chemicals, heavy metal pollution is becoming increasingly serious. Among these heavy metal ions, the hazards caused by various chromium compounds (Cr) cannot be ignored. The biological toxicity, carcinogenicity and easy migration of Cr(VI) in water environments make the detection and treatment of chromium-containing wastewater an environmental problem that needs to be solved urgently. At present, bio-based and biodegradable materials have received widespread attention, especially biomaterials for the development and production of polymer materials, reagents, chips, interferons, sensors, and cellulose biochemical products using non-food biomass as raw materials. Therefore, the development of a simple, rapid and convenient biodegradable fluorescent sensor for the selective detection of Cr(VI) is urgently needed.

[0003] Compared to traditional heavy metal ion detection methods that rely on large, precision instruments, homogeneous fluorescence sensors, while offering high sensitivity, no need for a reference system, and rich output signals, are still limited by their difficulties in device fabrication, reusability, and potential contamination of the target system. With the development of smart sensors, thin-film fluorescence sensors have made significant progress, owing to their portability, ease of device fabrication, reusability, and lack of contamination. Fluorescent gel film sensors, an innovative branch of fluorescence sensors, cleverly combine the stability of solids with the dynamic exchange properties of solutions, making them particularly suitable for monitoring heavy metal ions in aqueous environments. Furthermore, these gel-based materials are often biodegradable, contributing to environmental protection. Recently, fluorescent films based on various luminophores and functional materials have been reported for Cr(VI) detection. However, contact between thin-film fluorescence sensors and ions primarily relies on the film's pores. Insufficient contact between the target ions and the sensing element results in low sensitivity and long response times. Therefore, the development of biodegradable thin-film fluorescence sensors for rapid and sensitive detection of heavy metal ions in the environment holds potential value in environmental monitoring and public health protection. Summary of the Invention

[0004] The purpose of the present invention is to provide a conjugated polymer precursor and its preparation, a conjugated polymer and its preparation and application, a hydrogel thin film fluorescence sensor and its preparation and application, and a biodegradation method, so as to achieve high selectivity and high sensitivity of the thin film fluorescence sensor.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a conjugated polymer precursor having a structure shown in Formula 1:

[0007]

[0008] The present invention provides a method for preparing the conjugated polymer precursor described in the above technical solution, comprising the following steps:

[0009] 1-pyrene methanol, tert-butyldimethylchlorosilane, imidazole and an organic solvent are mixed and subjected to a silane coupling reaction to obtain a conjugated polymer precursor.

[0010] Preferably, the molar ratio of 1-pyrene methanol, tert-butyldimethylchlorosilane and imidazole is 1.0:1.05-1.5:1-2.

[0011] The present invention provides a conjugated polymer having a structure shown in Formula 2:

[0012]

[0013] In Formula 2, n=2 to 100, and n is a natural number.

[0014] The present invention provides a method for preparing the conjugated polymer described in the above technical solution, comprising the following steps:

[0015] In a three-electrode system, a conjugated polymer precursor is subjected to constant potential polymerization in an electrolyte to obtain a conjugated polymer; the conjugated polymer precursor is the conjugated polymer precursor described in the above technical solution.

[0016] Preferably, the electrolyte consists of tetrabutylammonium hexafluorophosphate and dichloromethane; the concentration of the tetrabutylammonium hexafluorophosphate in the electrolyte is 0.1 to 0.5 mol / L; the concentration of the conjugated polymer precursor in the electrolyte is 0.01 to 1 mol / L;

[0017] The potential of the constant potential polymerization is 1.1-1.4V, the scanning speed is 50-100mV / s, and the polymerization time is 2-48h.

[0018] The present invention provides the use of the conjugated polymer described in the above technical solution or the conjugated polymer prepared by the preparation method described in the above technical solution in a thin film fluorescence sensor.

[0019] The present invention provides a method for preparing a hydrogel film fluorescence sensor, comprising the following steps:

[0020] mixing sodium alginate, polyvinyl alcohol and water to obtain a gel solution;

[0021] mixing the conjugated polymer with an organic solvent to obtain a fluorescent mother solution;

[0022] Mixing the fluorescent mother solution with the gel solution, and performing 3D printing on the resulting mixture to obtain a fluorescent gel film;

[0023] soaking the fluorescent gel film in a calcium-containing crosslinking agent solution to perform crosslinking, and subjecting the obtained crosslinked film to a freeze-thaw cycle to obtain a hydrogel film fluorescent sensor;

[0024] The conjugated polymer is the conjugated polymer described in the above technical solution or the conjugated polymer prepared by the preparation method described in the above technical solution.

[0025] In the gel solution, the mass concentration of sodium alginate is 3-4%, and the mass concentration of polyvinyl alcohol is 7-10%;

[0026] The volume ratio of the fluorescent mother solution to the gel solution is 0.5-1:0.5-1;

[0027] The calcium-containing crosslinking agent solution is a CaCl2 solution, the concentration of the calcium-containing crosslinking agent solution is 0.1 to 0.5 mol / L, and the crosslinking time is 5 to 30 minutes;

[0028] The freeze-thaw process includes freezing at -20 to -50°C for 2 to 24 hours and then thawing; the number of cycles is 3 to 6 times.

[0029] The present invention provides a hydrogel film fluorescence sensor prepared by the preparation method described in the above technical solution.

[0030] The present invention provides the use of the hydrogel film fluorescence sensor described in the above technical solution in detecting chromate ions.

[0031] The present invention provides a method for biodegrading the hydrogel film fluorescence sensor described in the above technical solution, comprising the following steps:

[0032] After the hydrogel film fluorescent sensor is immersed in an alcohol solution to remove the conjugated polymer, the obtained solid matter is degraded; the bacterial colony used for the degradation is Penicillium or Alcaligenes faecalis.

[0033] The present invention provides a conjugated polymer. The polypyrene in the pyrene-based conjugated polymer not only has a unique "molecular line effect" that can amplify the fluorescent signal, thereby improving its detection sensitivity and quantum yield, but also can utilize the Si and O groups contained in the side chain to specifically identify chromate ions.

[0034] The present invention adopts a hydrogel construction strategy, combining the stability of solids with the dynamic exchange characteristics of solutions, increasing ion channels and specific surface area, and promoting the contact between the ions to be measured and the sensing unit. This solves the problem of low detection sensitivity and long response time of thin-film sensors caused by insufficient contact between the ions to be measured and the sensing unit, and expands the application of thin-film fluorescence sensors with conjugated polymers as sensing units in specific sensing scenarios.

[0035] The present invention adopts 3D printing to prepare the conjugated polymer, sodium alginate and polyvinyl alcohol into a thin film fluorescence sensor with the conjugated polymer as a sensing unit and sodium alginate and polyvinyl alcohol as a gel substrate.

[0036] The hydrogel film fluorescent sensor prepared by 3D printing in the present invention has good sensing performance and biodegradable characteristics, can be recycled and reused, has controllable shape, low cost, is environmentally friendly, and has strong adaptability to various detection environments. It provides an innovative and pragmatic method for the development of environmentally friendly and sustainable fluorescent sensors, and solves the problems of traditional fluorescent sensors that are difficult to degrade and have high production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the conjugated polymer precursor prepared in Example 1;

[0038] Figure 2 This is the LSV diagram of the conjugated polymer precursor prepared in Example 1 in a tetrabutylammonium hexafluorophosphate-dichloromethane solution system;

[0039] Figure 3 CV curve of the conjugated polymer precursor prepared in Example 1;

[0040] Figure 4 Flow chart of the 3D printing preparation of the hydrogel film fluorescence sensor in Example 1;

[0041] Figure 5 This is a graph showing the ion selectivity test of the hydrogel film fluorescence sensor prepared in Example 1;

[0042] Figure 6 This is a sensitivity analysis diagram of the hydrogel film fluorescence sensor prepared in Example 1 to chromate ions;

[0043] Figure 7 This is a comparison of the hydrogel film fluorescence sensor prepared in Example 1 before and after biodegradation;

[0044] Figure 8 This is a bar graph showing the change in mass of the hydrogel film fluorescence sensor prepared in Example 1 versus degradation time. DETAILED DESCRIPTION

[0045] The present invention provides a conjugated polymer precursor having a structure shown in Formula 1:

[0046]

[0047] The present invention provides a method for preparing the conjugated polymer precursor described in the above technical solution, comprising the following steps:

[0048] 1-pyrene methanol, tert-butyldimethylchlorosilane, imidazole and an organic solvent are mixed and subjected to a silane coupling reaction to obtain a conjugated polymer precursor.

[0049] In the present invention, the molar ratio of 1-pyrene methanol, tert-butyldimethylchlorosilane and imidazole is 1.0:1.05-1.5:1-2, more preferably 1.0:1.05:1.1.

[0050] In the present invention, the organic solvent is preferably tetrahydrofuran; the present invention has no special limitation on the amount of the organic solvent, which can be adjusted according to actual needs.

[0051] In the present invention, the temperature of the silane coupling reaction is preferably room temperature, and the time is preferably 8 to 24 hours, more preferably 12 to 24 hours.

[0052] The present invention preferably mixes 1-pyrene methanol and tert-butyldimethylsilyl chloride (TBS-Cl) in an organic solvent, adds imidazole, and refluxes at room temperature under nitrogen conditions to carry out a silane coupling reaction. After quenching the reaction with water, the mixture is extracted with dichloromethane, and then the organic layer is dried and concentrated, eluted by silica gel column chromatography (eluents are ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 3:7), and vacuum dried to obtain a conjugated polymer precursor.

[0053] The present invention provides a conjugated polymer having a structure shown in Formula 2:

[0054]

[0055] In Formula 2, n=2 to 100, and n is a natural number.

[0056] In the present invention, n is preferably 3.

[0057] The present invention provides a method for preparing the conjugated polymer described in the above technical solution, comprising the following steps:

[0058] In a three-electrode system, a conjugated polymer precursor is subjected to constant potential polymerization in an electrolyte to obtain a conjugated polymer;

[0059] The conjugated polymer precursor has a structure shown in Formula 2:

[0060]

[0061] In the present invention, unless otherwise specified, the required raw materials or reagents are commercially available products well known to those skilled in the art.

[0062] In the present invention, in the three-electrode system, the reference electrode used is Ag / AgCl, and the counter electrode and working electrode used are both rectangular ITO conductive glass with a length of 1.5 cm and a width of 1 cm.

[0063] In the present invention, the electrolyte is preferably composed of tetrabutylammonium hexafluorophosphate and dichloromethane; the concentration of the tetrabutylammonium hexafluorophosphate in the electrolyte is preferably 0.1 to 0.5 mol / L, more preferably 0.1 mol / L; the concentration of the conjugated polymer precursor in the electrolyte is preferably 0.01 to 1 mol / L, more preferably 0.05 mol / L; the tetrabutylammonium hexafluorophosphate serves as a supporting electrolyte.

[0064] In the present invention, the potential of the constant potential polymerization is preferably 1.1-1.4 V, more preferably 1.3 V, the scanning speed is preferably 50-100 mV / s, more preferably 100 mV / s; the polymerization time is preferably 2-48 h, more preferably 24 h.

[0065] After the constant potential polymerization is completed, the present invention preferably washes the obtained conjugated polymer film repeatedly with acetonitrile and then dries it at 60° C. to obtain a conjugated polymer.

[0066] The present invention provides the use of the conjugated polymer described in the above technical solution or the conjugated polymer prepared by the preparation method described in the above technical solution in a thin film fluorescence sensor.

[0067] The present invention provides a method for preparing a hydrogel film fluorescence sensor, comprising the following steps:

[0068] mixing sodium alginate, polyvinyl alcohol and water to obtain a gel solution;

[0069] mixing the conjugated polymer with an organic solvent to obtain a fluorescent mother solution;

[0070] Mixing the fluorescent mother solution with the gel solution, and performing 3D printing on the resulting mixture to obtain a fluorescent gel film;

[0071] soaking the fluorescent gel film in a calcium-containing crosslinking agent solution to perform crosslinking, and subjecting the obtained crosslinked film to a freeze-thaw cycle to obtain a hydrogel film fluorescent sensor;

[0072] The conjugated polymer is the conjugated polymer described in the above technical solution or the conjugated polymer prepared by the preparation method described in the above technical solution.

[0073] In the present invention, in the gel solution, the mass concentration of sodium alginate is preferably 3-4%, more preferably 3%, and the mass concentration of polyvinyl alcohol is preferably 7-10%, more preferably 8%; the present invention preferably mixes water, sodium alginate and polyvinyl alcohol, and stirs at a constant temperature of 70°C until the solid particles are completely melted to obtain a gel solution.

[0074] Polyvinyl alcohol not only has excellent mechanical properties (especially high tensile strength), but also can be biodegraded in humid environments such as sewage sludge, river water and seawater (biodegradable water-soluble polymer). After microbial decomposition, it is mainly reduced to the environment as CO2 and H2O, and will not cause white pollution. Cross-linked polyvinyl alcohol only needs to form hydrogen bonds between and within the polyvinyl alcohol chain molecules and a three-dimensional network of microcrystalline regions at low temperatures. Sodium alginate has good degradability, and the mechanical properties can be improved by compounding sodium alginate with polyvinyl alcohol. Sodium alginate fragments are rich in α-L-guluronic acid (α-L-guluronic, G) units, which can react with Ca 2+ An "egg-box" structure is formed, which accumulates to form a cross-linked network structure, thus forming a hydrogel.

[0075] In the present invention, the organic solvent is preferably N,N-dimethylformamide; the conjugated polymer is dissolved in the organic solvent and filtered through a membrane to obtain a fluorescent mother solution; the concentration of the conjugated polymer in the fluorescent mother solution is preferably 0.08 to 0.1 g / L, more preferably 0.09 g / L.

[0076] In the present invention, the volume ratio of the fluorescent mother solution to the gel solution is preferably 0.5-1:0.5-1, more preferably 1:1;

[0077] The present invention preferably adds the fluorescent mother liquor to the gel solution at 70°C, and uses the resulting mixture as 3D printing ink for 3D printing to produce a fluorescent gel film. The dispensing speed of the 3D printing is preferably 15 mm / s, and the dispensing pressure is preferably 200 kPa. The present invention preferably uses a DB 100 3D printer for printing the ink, with a nozzle size of 90 to 250 μm. The printing path is generated by drawing in Adobe Illustrator and converted into a scalable vector graphic.

[0078] In the present invention, the calcium-containing crosslinking agent solution is preferably a CaCl2 solution, more preferably a CaCl2 aqueous solution, the concentration of the calcium-containing crosslinking agent solution is preferably 0.1-0.5 mol / L, more preferably 0.1 mol / L, and the crosslinking time is preferably 5-30 min, more preferably 5 min.

[0079] In the present invention, the freeze-thaw process preferably includes freezing at -20 to -50°C for 2 to 24 hours and then thawing, more preferably freezing for 6 hours; the number of cycles is preferably 3 to 6 times, more preferably 3 times.

[0080] The present invention provides a hydrogel film fluorescence sensor prepared by the preparation method described in the above technical solution.

[0081] The present invention provides the use of the hydrogel film fluorescence sensor described in the above technical solution in detecting chromate ions. The present invention has no particular limitation on the method of the application, and the application can be carried out according to methods well known in the art.

[0082] The present invention provides a method for biodegrading the hydrogel film fluorescence sensor described in the above technical solution, comprising the following steps:

[0083] After the hydrogel film fluorescent sensor is immersed in an alcohol solution to remove the conjugated polymer, the obtained solid matter is degraded; the bacterial colony used for the degradation is Penicillium or Alcaligenes faecalis.

[0084] In the present invention, the alcohol solution is preferably an ethanol solution, and the volume concentration of the alcohol solution is preferably 75-95%, more preferably 75%.

[0085] After removing the conjugated polymer in the alcohol solution, the present invention washes the obtained solid matter with water to remove the alcohol and then degrades it.

[0086] The present invention preferably uses Penicillium or Alcaligenes faecalis for degradation; the degradation conditions are preferably: relative humidity of 75% and temperature of 29°C.

[0087] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0088] Example 1

[0089]

[0090] 1-Pyrene methanol (1.8582 g, 8 mmol), TBS-Cl (1.266 g, 8.4 mmol) and tetrahydrofuran (20 mL) were added to a round-bottom flask and mixed, and then imidazole (0.5991 g, 8.8 mmol) was added. The mixture was refluxed under nitrogen at room temperature for 24 h, and the reaction was quenched with 100 mL of water. The organic layer was extracted with dichloromethane, and then dried and concentrated. The organic layer was eluted by silica gel column chromatography (eluent: ethyl acetate and petroleum ether, the volume ratio of ethyl acetate and petroleum ether was 3:7), and then dried under vacuum to obtain a light yellow solid, i.e., a conjugated polymer precursor.

[0091] A one-chamber three-electrode system was used, with Ag / AgCl as the reference electrode and 1.5 cm×1 cm rectangular ITO conductive glass as the counter electrode and working electrode at a constant voltage of 1.3 V. The prepared conjugated polymer precursor was subjected to constant potential polymerization in a dichloromethane solution of tetrabutylammonium hexafluorophosphate (the concentration of tetrabutylammonium hexafluorophosphate in the electrolyte was 0.1 mol / L, and the concentration of the conjugated polymer precursor in the electrolyte was 0.05 mol / L) for 24 h at a scan rate of 100 mV / s. The resulting polymer film was repeatedly washed with acetonitrile to remove unpolymerized monomers, and then vacuum-dried at 60°C to obtain a conjugated polymer (n=3).

[0092] like Figure 4 As shown, the prepared conjugated polymer was dissolved in N,N-dimethylformamide and filtered to prepare 10 mL of 0.09 g / L fluorescent mother solution. 1.6 g of polyvinyl alcohol and 0.6 g of sodium alginate were added to 20 mL of deionized water and stirred at 70°C until the solid particles were completely melted to obtain a gel solution. 10 mL of the gel solution was heated and mixed with 10 mL of the fluorescent mother solution at 70°C to obtain a 3D printing ink. The ink was printed using a DB100 3D printer with a nozzle size of 90 to 250 μm, a dispensing speed of 15 mm / s, and a dispensing pressure of 200 kPa. The printing path was generated by drawing in Adobe Illustrator and converted into a scalable vector graphic. After printing, the resulting gel film was immersed in a 0.1 mol / L CaCl2 aqueous solution for cross-linking for 5 minutes, then taken out, frozen at -20°C for 6 hours, thawed, and the freeze-thaw step was repeated three times to obtain a hydrogel film fluorescent sensor.

[0093] Characterization and testing

[0094] 1) Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the conjugated polymer precursor prepared in Example 1. The data obtained are 1 H NMR (400 MHz, DMSO), δ (ppm): 8.30 (ddd, J = 21.2, 18.1, 9.2 Hz, 5H), 8.19-8.04 (m, 4H), 5.46 (s, 2H), 0.92 (s, 9H), 0.14 (s, 6H). This demonstrates the successful synthesis of the structural polymer precursor.

[0095] 2) Figure 2 This is an LSV diagram (scan rate of 100 mV / s) of the conjugated polymer precursor prepared in Example 1 in a tetrabutylammonium hexafluorophosphate-dichloromethane solution (tetrabutylammonium hexafluorophosphate concentration is 0.1 mol / L) system. The concentration of the conjugated polymer precursor in the tetrabutylammonium hexafluorophosphate-dichloromethane solution system is 0.01 mol / L. Figure 2It can be seen that the initial oxidation potential of the conjugated polymer is 1.05 V. A lower initial oxidation potential is conducive to obtaining a high-quality polymer film.

[0096] 3) Figure 3 The CV curve of the conjugated polymer precursor prepared in Example 1 in the voltage range of 0 to 1.2 V (scan rate of 100 mV / s); Figure 3 It can be seen that the current density of the conjugated polymer precursor increases with the increase of the scanning cycle number.

[0097] 4) Application Testing

[0098] The hydrogel film fluorescence sensor prepared in Example 1 was used for chromate ion detection. The specific method was to immerse the hydrogel film fluorescence sensor in aqueous solutions containing different anions and cations (see ion types for details). Figure 5 The concentration of each ion is 10 -4 mol / L) for 3 s and then the fluorescence intensity was measured using a fluorescence spectrometer; Figure 5 Blank in the middle refers to a blank, and a single hydrogel film was tested.

[0099] Figure 5 This is a test diagram of the ion selectivity of the hydrogel film fluorescence sensor prepared in Example 1; Figure 5 It can be seen that the sensor has specific selectivity for chromate ions.

[0100] The chromate concentration is set to 10 -9 ~10 -1 mol / L range of gradient solutions (concentrations were 1.4.98×10 - 9 mol / L; 2.3.85×10 -8 mol / L; 3.8.45×10 -8 mol / L; 4.2.40×10 -7 mol / L; 5.6.80×10 -7 mol / L; 6.1.56×10 -6 mol / L; 7.8.40×10 -6 mol / L; 8.2.45×10 -5 mol / L; 9.6.95×10 -5 mol / L; 10.1.32×10 -4 mol / L; 11.5.54×10 -4 mol / L; 12.1.81×

[0101] 10 -3 mol / L; 13.7.86×10 -3mol / L; 14.2.41×10 -2 mol / L; 15.9.41×10 -2 mol / L; 16.2×10 -1 mol / L), the hydrogel film fluorescence sensor prepared in Example 1 was immersed in chromate solutions of different concentrations for 3 seconds and then taken out, and its fluorescence intensity was measured using a fluorescence spectrometer. Figure 6 This is a sensitivity analysis diagram of the hydrogel film fluorescence sensor prepared in Example 1 to chromate ions. Figure 6 The inset in the middle is the linear curve formed by the chromate gradient solution and the fluorescence intensity; Figure 6 It can be seen that the hydrogel film can detect chromate ions at the micromole level in real time.

[0102] 5) Degradation test

[0103] The hydrogel film fluorescent sensor prepared in Example 1 was biodegraded by immersing the hydrogel film fluorescent sensor in a 75% ethanol solution to remove the conjugated polymer, then immersing it in deionized water to wash off the ethanol, and culturing the sensor in a constant temperature incubator using Penicillium and Alcaligenes faecalis as degradation colonies, respectively, while maintaining a relative humidity of 75% and a temperature of 29°C.

[0104] Figure 7 This is a comparison of the hydrogel film fluorescence sensor prepared in Example 1 before and after biodegradation; Figure 7 As shown in the figure, as the degradation process progresses, bacterial colonies continue to multiply on the sample surface and the morphology of the solid also changes significantly, indicating that the hydrogel substrate is harmless to bacteria. Penicillium and Alcaligenes faecalis used for polyvinyl alcohol degradation can still biodegrade the gel substrate composited with sodium alginate.

[0105] The degradation results are shown in the following figure: Figure 8 As shown; Figure 8 The bar graph shows the change of the mass of the hydrogel film fluorescence sensor prepared in Example 1 with the degradation time. Figure 8 It can be seen that after 7 days, the mass loss rates of the hydrogel film fluorescence sensor were 3.54% and 4.85%, respectively, indicating that the hydrogel substrate is a highly potential fully biodegradable green gel substrate.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A conjugated polymer, characterized in that It has the structure shown in formula 2: Formula 2; In formula 2, n=2~100, and n is a natural number.

2. The method for preparing the conjugated polymer according to claim 1, wherein The following steps are involved: In a three-electrode system, a conjugated polymer precursor is subjected to constant potential polymerization in an electrolyte to obtain a conjugated polymer; The conjugated polymer precursor has a structure shown in Formula 1: Formula 1.

3. The preparation method according to claim 2, characterized in that The electrolyte consists of tetrabutylammonium hexafluorophosphate and dichloromethane; the concentration of the tetrabutylammonium hexafluorophosphate in the electrolyte is 0.1-0.5 mol / L; the concentration of the conjugated polymer precursor in the electrolyte is 0.01-1 mol / L; The potential of the constant potential polymerization is 1.1-1.4 V, the scanning speed is 50-100 mV / s, and the polymerization time is 2-48 h.

4. Use of the conjugated polymer according to claim 1 or the conjugated polymer prepared by the preparation method according to any one of claims 2 to 3 in a thin film fluorescence sensor.

5. A method for preparing a hydrogel film fluorescence sensor, characterized in that: The following steps are involved: mixing sodium alginate, polyvinyl alcohol and water to obtain a gel solution; mixing the conjugated polymer with an organic solvent to obtain a fluorescent mother solution; Mixing the fluorescent mother solution with the gel solution, and performing 3D printing on the resulting mixture to obtain a fluorescent gel film; soaking the fluorescent gel film in a calcium-containing crosslinking agent solution to perform crosslinking, and subjecting the obtained crosslinked film to a freeze-thaw cycle to obtain a hydrogel film fluorescent sensor; The conjugated polymer is the conjugated polymer according to claim 1 or the conjugated polymer prepared by the preparation method according to any one of claims 2 to 3.

6. The preparation method according to claim 5, characterized in that In the gel solution, the mass concentration of sodium alginate is 3-4%, and the mass concentration of polyvinyl alcohol is 7-10%; The volume ratio of the fluorescent mother solution to the gel solution is 0.5~1:0.5~1; The calcium-containing crosslinking agent solution is a CaCl2 solution, the concentration of the calcium-containing crosslinking agent solution is 0.1-0.5 mol / L, and the crosslinking time is 5-30 min; The freeze-thaw process includes freezing at -20 to -50°C for 2 to 24 hours and then thawing; the number of cycles is 3 to 6 times.

7. A hydrogel film fluorescence sensor prepared by the preparation method according to any one of claims 5 to 6.

8. Use of the hydrogel film fluorescence sensor according to claim 7 in detecting chromate ions.

9. The biodegradation method of the hydrogel film fluorescence sensor according to claim 7, characterized in that: The following steps are involved: After the hydrogel film fluorescent sensor is immersed in an alcohol solution to remove the conjugated polymer, the obtained solid matter is degraded; the bacterial colony used for the degradation is Penicillium or Alcaligenes faecalis.

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