Polymer of a terthiophene alkyl sulfonic acid, its preparation method and application

Abstract

The present invention discloses a trithiophene alkyl sulfonic acid polymer, a preparation method and an application thereof. The structure of the trithiophene alkyl sulfonic acid polymer is shown in Formula I. The present invention also provides a preparation method of the polymer shown in Formula I. The synthesis route of the present invention is simple, the synthesis steps are few, and most of the synthesized materials are commercial materials, which is conducive to large-scale synthesis. The trithiophene alkyl sulfonic acid polymer of the present invention is used as a material, and has different ionic thermoelectric properties under different humidity conditions, and at a relative humidity of 90%, the power factor can be as high as 148.98μW / m / K. 2 The polymer of formula I provided by the present invention has a good application prospect in ionic thermoelectric materials.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer materials, and particularly relates to a polymeric polymer of alkyl sulfonic acid of terthiophene and a preparation method and application thereof. BACKGROUND

[0002] Abundant heat is generated in the process of family, industry and nature, and most of the heat is dissipated in the environment as waste heat due to low heat utilization efficiency. Therefore, collecting waste heat is of great significance to sustainable development. The working principle of thermoelectric materials is based on the Seebeck effect, which can directly convert heat into electricity. In recent years, ion conductors such as ion polymer conductors and gel ion conductors are expected to become a new generation of thermoelectric materials due to their high thermoelectric power. The thermal power of such ion conductors is usually 2-3 orders of magnitude higher than that of traditional electronic thermoelectric materials. Organic ion thermoelectric materials use ion conductive materials as carriers and conduct through the free movement of ions in the material. They have important application value in supercapacitors, ion batteries, electrochromic displays and the like.

[0003] Organic ion thermoelectric materials mainly include organic salt solutions, polymer electrolytes, ion / electron mixed conductors and ionic liquids. Compared with other types of organic ion thermoelectric materials, the polymer electrolyte has a higher ion Seebeck coefficient because only one kind of charge can move freely in the polymer electrolyte, while the other charge of the opposite sign is fixed on the polymer backbone. Polymer electrolytes include polystyrene sulfonic acid and its metal salt, perfluorosulfonic acid and its metal salt, and composites composed of a non-ion conductive polymer matrix and an electrolyte. In recent years, the research on polymer electrolyte materials in the field of ion thermoelectricity has entered a new stage. The development of new polymer electrolyte materials and the expansion of the field of polymer electrolyte materials have become the focus of future research on ion thermoelectric materials. Therefore, the design and synthesis of new polymer electrolytes are of great significance to the research on ion thermoelectric materials. SUMMARY

[0004] The purpose of the present application is to provide a polymer of alkyl sulfonic acid of terthiophene and a preparation method and application thereof.

[0005] The polymer of alkyl sulfonic acid of terthiophene provided by the present application has a structural formula as shown in formula I:

[0006]

[0007] In the polymer shown in formula I, n is 5-500, and specifically n is 50-300.

[0008] m is an integer in the range of 4-10, and specifically can be 4-6, and more specifically can be 4, 5 or 6.

[0009] The polymer represented by the above formula I is prepared by a method comprising the following steps:

[0010] In the presence of an oxidizing-reducing agent, the compound represented by formula V is polymerized in a sulfuric acid aqueous solution to obtain a polymer represented by formula I.

[0011]

[0012] In Formula V, m has the same definition as in Formula I above.

[0013] In the above method, the oxidation-reduction agent is ferrous sulfate heptahydrate-sodium persulfate;

[0014] The molar ratio of the compound represented by formula V, ferrous sulfate heptahydrate and sodium persulfate can be 1.0:0.55-0.65:1.95-2.05, specifically 1.0:0.6:2.

[0015] The polymerization reaction temperature is 15-35°C, preferably 20-30°C, specifically 25°C;

[0016] The time is 12 to 48 hours, specifically 24 hours.

[0017] The polymerization reaction is carried out in an inert atmosphere; the atmosphere may specifically be an argon atmosphere;

[0018] The sulfuric acid aqueous solution is a 1 mol / L sulfuric acid aqueous solution.

[0019] In the above method, the compound represented by formula V as the starting material can be prepared according to the following steps:

[0020] (1) 4-methoxyphenol reacts with a dibromoalkane represented by Formula 1 (m is an integer between 4 and 10) in a potassium carbonate solution to obtain a compound represented by Formula II;

[0021]

[0022] In the above formula II, m is 4-10, specifically 4, 5 or 6.

[0023] (2) reacting the compound of formula II obtained in step 1) with magnesium chips, zinc bromide, 3,5-dibromo-dithieno[3,2-b:2′,3′-d]thiophene and a palladium catalyst in three consecutive steps to obtain a compound of formula III;

[0024]

[0025] In the above formula III, m is 4-10, specifically 4, 5 or 6;

[0026] (3) reacting the compound represented by formula III obtained in step 2) with boron tribromide to obtain the compound represented by formula IV after completion of the reaction;

[0027]

[0028] In the above formula IV, m is 4-10, specifically 4, 5 or 6;

[0029] (4) reacting the compound represented by Formula IV obtained in step 3) with sodium sulfite in a mixed solvent of water and ethanol to obtain a compound represented by Formula V after completion of the reaction;

[0030]

[0031] In step 1) of the above method, the dibromoalkane may be at least one of 1,4-dibromobutane, 1,5-dibromopentane, or 1,6-dibromohexane;

[0032] The molar ratio of 4-methoxyphenol, dibromoalkane and potassium carbonate is 1:5.95-6.05:5.95-6.05;

[0033] The reaction temperature is 75-85°C and the reaction time is 12-24 hours;

[0034] In the step 2), the palladium catalyst is [1,1′-bis(diphenylphosphino)ferrocene]palladium dichloride;

[0035] The molar ratio of the compound represented by formula II, magnesium chips, zinc bromide, 3,5-dibromo-dithieno[3,2-b:2′,3′-d]thiophene and palladium catalyst is 3-6:3.3-6.6:3.3-6.6:1:0.1-0.2, specifically 4:4.4:4.4:1:0.15;

[0036] The reaction temperature is 60-130°C, specifically 90°C, and the reaction time is 72-96 hours, specifically 84 hours;

[0037] In the step 3), the molar ratio of the compound represented by formula III to boron tribromide is 1:1.9-2.1, specifically 1:2;

[0038] The reaction temperature is 35 to 45° C., specifically 40° C.; the reaction time is 6 to 18 hours, specifically 12 hours;

[0039] In the step 4), the molar ratio of the compound represented by formula IV to sodium sulfite is 1:5.8-6.2, specifically 1:6;

[0040] The reaction temperature is 80-100° C., specifically 90° C.; the reaction time is 40-50 hours, specifically 48 hours;

[0041] The reactions from step 1) to step 4) are all carried out in a solvent.

[0042] In the step 1), the solvent is acetone;

[0043] In the step 2), the solvent is tetrahydrofuran;

[0044] In the step 3), the solvent is dichloromethane;

[0045] In the step 4), the solvents are water and ethanol, and the volume ratio is 1:1.

[0046] The synthetic route of the above method is as follows Figure 1 shown.

[0047] The use of the polymer represented by the above formula I as an organic ionic thermoelectric material or in the preparation of an organic ionic thermoelectric material also falls within the scope of protection of the present invention.

[0048] The advantages of the present invention are:

[0049] 1. The raw materials for the synthesis of 3,5-dibromo-dithieno[3,2-b:2′,3′-d]thiophene and intermediates can be easily synthesized or purchased in large quantities from commercial channels. The synthetic route is simple, with few synthetic steps, high yield, and easy to large-scale synthesis;

[0050] 2. Trithienyl alkyl sulfonic acid polymers have high molecular weight and good solubility in aqueous solution, making them promising candidates for the preparation of high-performance organic ionic thermoelectric devices via spin coating.

[0051] 3. As an organic ionic thermoelectric material, the trithiophene alkyl sulfonic acid polymer has excellent ionic thermoelectric properties and has good commercial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The synthetic route of the trithienylalkylsulfonic acid polymer represented by formula I of the present invention is shown in FIG.

[0053] Figure 2 The UV-visible absorption spectra of the polymer PDTTBS, PDTTPS and PDTTHS films of the present invention are shown.

[0054] Figure 3 1 is the cyclic voltammogram of the polymers PDTTBS, PDTTPS and PDTTHS of the present invention.

[0055] Figure 4 The graph shows the potential difference generated across the polymer PDTTBS of the present invention at different humidity levels (70%, 80% and 90%) when a temperature difference of 0.61 Kelvin is applied.

[0056] Figure 5 The graph shows the potential difference generated across the polymer PDTTPS of the present invention at different humidity levels (70%, 80% and 90%) when a temperature difference of 0.61 Kelvin is applied.

[0057] Figure 6 The graph shows the potential difference generated across the polymer PDTTHS of the present invention at different humidity levels (70%, 80% and 90%) when a temperature difference of 0.61 Kelvin is applied.

[0058] Figure 7 Graph showing the performance parameters of conductivity, ion Seebeck and power factor of the polymers PDTTBS, PDTTPS and PDTTHS of the present invention at 70%, 80% and 90% humidity. DETAILED DESCRIPTION

[0059] The present invention will be further described in detail below in conjunction with specific embodiments. The examples provided are only for illustrating the present invention and are not intended to limit the scope of the present invention. The examples provided below can serve as a guide for further improvements by those skilled in the art and are not intended to limit the present invention in any way.

[0060] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples, unless otherwise specified, were all commercially available.

[0061] Example 1. Synthesis of polymer PDTTBS

[0062] 1) Synthesis of compound of formula II

[0063] 1,4-Dibromobutane (6.48 g, 30 mmol) was added to a solution of 4-methoxyphenol (0.621 g, 5 mmol) and potassium carbonate (4.146 g, 30 mmol) in acetone (150 mL). The reaction system was then heated under reflux at 75°C with stirring overnight. After completion of the reaction, the potassium carbonate was filtered off, and the organic phase was spin-dried. The crude product was separated by silica gel column chromatography to obtain the desired product, 1-(4-bromobutoxy)-4-methoxybenzene, as a white solid (0.989 g, yield: 76%).

[0064] The structural characterization data are as follows:

[0065] 1-(4-Bromobutoxy)-4-methoxybenzene:

[0066] Mass spectrometry: GC-MS (m / z): [M] + :257.9

[0067] Hydrogen spectrum: 1 H NMR (300 MHz, CDC13) δ (ppm): 6.83 (s, 4H), 3.95 (t, J = 8, 2H), 3.77 (s, 3H), 3.49 (t, J = 8, 2H), 2.07 (m, 2H), 1.92 (m, 2H)

[0068] 1 -(5-bromopentyloxy)-4-methoxybenzene:

[0069] Mass spectrum: GC-MS (m / z): [M] + : 271.8

[0070] Hydrogen spectrum: 1 H NMR (300 MHz, CDC13) δ (ppm): 6.83 (s, 4H), 3.92 (t, J = 8, 2H), 3.77 (s, 3H), 3.44 (t, J = 8, 2H), 1.94 (m, 2H), 1.77 (m, 2H), 1.62 (m, 2H)

[0071] 1 -(6-bromohexyloxy)-4-methoxybenzene:

[0072] Mass spectrum: GC-MS (m / z): [M] + : 286.1

[0073] Hydrogen spectrum: 1 H NMR (300 MHz, CDC13) δ (ppm): 6.83 (s, 4H), 3.91 (t, J = 8, 2H), 3.77 (s, 3H), 3.42 (t, J = 8, 2H), 1.90 (m, 2H), 1.78 (m, 2H), 1.50 (m, 4H)

[0074] 2) Synthesis of Compound III: Under an argon atmosphere, approximately 20 mL of a solution of 1-(4-bromobutoxy)-4-methoxybenzene (21.95 g, 84.7 mmol) in tetrahydrofuran (250 mL) was slowly added dropwise to a mixture of magnesium turnings (2.256 g, 93.2 mmol) and tetrahydrofuran (5 mL). The mixture was stirred at room temperature until the reaction was initiated. The remaining 230 mL of the 1-(4-bromobutoxy)-4-methoxybenzene solution in tetrahydrofuran was then slowly added to the reaction system. The mixture was stirred at room temperature for 2 hours and then heated to 85°C with stirring for 10 hours. After cooling to room temperature, the reaction mixture was added to a flask containing zinc bromide (20.99 g, 93.2 mmol) at -78°C under argon protection. After completion, the reaction system was slowly returned to room temperature and stirred overnight. 3,5-Dibromodithiophene[3,2-B:2',3'-D]thiophene (6 g, 16.94 mmol) and [1,1′-bis(diphenylphosphino)ferrocene]palladium dichloride (614 g, 0.847 mmol) were added to the reaction system and heated under reflux with stirring for three days. After completion, the reaction mixture was quenched by pouring it into 0.1 mol / L hydrochloric acid solution (200 mL). The mixture was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated to dryness. The crude product was separated by silica gel column chromatography to obtain 5.5 g of the target product, 3,5-bis(4-(4-methoxyphenoxy)butyl)dithiophene[3,2-B:2',3'-D]thiophene, as a yellow solid. Yield: 58.7%.

[0075] The structural characterization data are as follows:

[0076] 3,5-bis(4-(4-methoxyphenoxy)butyl)dithiophene[3,2-B:2',3'-D]thiophene:

[0077] Mass spectrometry: MALDI-TOF (m / z): [M] + :552.145

[0078] Proton spectrum: 1 H NMR (300MHz, CDCl3): δ (ppm): 6.98 (s, 2H), 6.82 (s, 8H), 3.95 (t, J = 8, 4H), 3.76 (s, 6H), 2.79 (t, J = 6, 4H), 1.97 (m, 4H), 1.85 (m, 4H)

[0079] 3,5-bis(5-(4-methoxyphenoxy)pentyl)dithiophene[3,2-B:2',3'-D]thiophene:

[0080] Mass spectrometry: MALDI-TOF (m / z): [M] + :580.178

[0081] Proton spectrum: 1 H NMR (300MHz, CDCl3): δ (ppm): 6.96 (s, 2H), 6.83 (s, 8H), 3.94 (t, J = 8, 4H), 3.76 (s, 6H), 2.77 (t, J = 6, 4H), 1.85 (m, 4H), 1.77-1.54 (m, 8H)

[0082] 3,5-bis(6-(4-methoxyphenoxy)hexyl)dithiophene[3,2-B:2',3'-D]thiophene:

[0083] Mass spectrometry: MALDI-TOF (m / z): [M] + :608.208

[0084] Proton spectrum: 1 H NMR (300MHz, CDCl3): δ (ppm): 6.95 (s, 2H), 6.82 (s, 8H), 3.90 (t, J = 8, 4H), 3.76 (s, 6H), 2.75 (t, J = 6, 4H), 1.76 (m, 4H), 1.56-1.26 (m, 12H)

[0085] 3) Synthesis of compound of formula IV

[0086] Under an argon atmosphere, a 1 mol / L solution of boron tribromide in dichloromethane (12 mL, 12 mmol) was added to a dichloromethane solution of the compound of Formula III: 3,5-bis(4-(4-methoxyphenoxy)butyl)dithiophene[3,2-B:2',3'-D]thiophene (2.16 g, 3.9 mmol). The mixture was heated to 60°C and stirred overnight. After completion of the reaction, the reaction mixture was poured into saturated ammonium chloride solution and extracted with dichloromethane. The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated to dryness. The crude product was separated by silica gel column chromatography to obtain 0.86 g of the desired product, 3,5-dibromobutyldithiophene[3,2-B:2',3'-D]thiophene, as a yellow liquid. Yield: 47.3%.

[0087] The structural characterization data are as follows:

[0088] 3,5-Dibromobutyldithiophene[3,2-B:2',3'-D]thiophene:

[0089] Mass spectrometry: MALDI-TOF (m / z): [M] + :465.979

[0090] Proton spectrum: 1H NMR (300MHz, CDCl3) δ (ppm): 6.99 (s, 2H), 3.45 (t, J = 8, 4H), 2.79 (t, J = 8, 4H), 1.98-1.90 (m, 8H)

[0091] 3,5-Dibromopentyldithiophene[3,2-B:2',3'-D]thiophene:

[0092] Mass spectrometry: MALDI-TOF (m / z): [M] + :493.923

[0093] Proton spectrum: 1 H NMR (300MHz, CDCl3) δ (ppm): 6.97 (s, 2H), 3.42 (t, J = 8, 4H), 2.76 (t, J = 8, 4H), 1.93 (m, 4H), 1.81 (m, 4H), 1.54 (m, 4H)

[0094] 3,5-Dibromohexyldithiophene[3,2-B:2',3'-D]thiophene:

[0095] Mass spectrometry: MALDI-TOF (m / z): [M] + :521.934

[0096] Proton spectrum: 1 H NMR (300MHz, CDCl3) δ (ppm): 6.97 (s, 2H), 3.40 (t, J = 8, 4H), 2.72 (t, J = 8, 4H), 1.87 (m, 4H), 1.77 (m, 4H), 1.54-1.40 (m, 8H)

[0097] 4) Synthesis of compound of formula V

[0098] Under an argon atmosphere, the compound of Formula IV (3,5-dibromobutyldithiophene[3,2-B:2',3'-D]thiophene) (1.254 g, 2.69 mmol) and sodium sulfite (1.254 g, 9.95 mmol) were dissolved in a mixture of deionized water (50 mL) and ethanol (50 mL) and heated under reflux for two days. After completion of the reaction, the reaction mixture was washed with dichloromethane, and the combined aqueous phases were spin-dried. The crude product was separated by reverse-phase column chromatography to yield 0.772 g of the target product, sodium 3,5-dibutyldithiophene[3,2-B:2',3'-D]thiophenesulfonate. The yield was 56%.

[0099] The structural characterization data are as follows:

[0100] Sodium 3,5-dibutylthiophenesulfonate [3,2-B:2',3'-D]thiophene:

[0101] Mass spectrometry: MALDI-TOF (m / z): [M+Na] + :534.900

[0102] Proton spectrum: 1 H NMR (300MHz, D2O) δ (ppm): 6.83 (s, 2H), 2.86 (t, J = 6, 4H), 2.52 (t, J = 6, 4H), 1.73-1.64 (m, 8H)

[0103] 3,5-Dipentylthiophene sodium sulfonate [3,2-B:2',3'-D]thiophene:

[0104] Mass spectrometry: MALDI-TOF (m / z): [M+Na] + :562.935

[0105] Proton spectrum: 1 H NMR (300MHz, D2O) δ (ppm): 6.71 (s, 2H), 2.76 (t, J = 6, 4H), 2.77 (t, J = 6, 4H), 1.66 (m, 4H), 1.45 (m, 4H)

[0106] 3,5-Dihexyl sodium thiophenesulfonate [3,2-B:2',3'-D]thiophene:

[0107] Mass spectrometry: MALDI-TOF (m / z): [M+Na] + :590.947

[0108] Proton spectrum: 1 H NMR (300MHz, D2O) δ (ppm): 6.60 (s, 2H), 2.74 (t, J = 6, 4H), 2.31 (t, J = 6, 4H), 1.56 (m, 4H), 1.34 (m, 4H), 1.07 (m, 8H)

[0109] 5) Synthesis of Formula I Polymers PDTTBS, PDTTPS, and PDTTHS

[0110] Under an argon atmosphere, the compound represented by Formula V (190 mg, 0.371 mmol) and ferrous sulfate heptahydrate (61.9 mg, 0.223 mmol) were dissolved in a 1M aqueous sulfuric acid solution. A solution of sodium persulfate (176.7 mg, 0.742 mmol) in water (1 mL) was then added dropwise to the reaction system and stirred at room temperature for 24 hours. After completion of the reaction, the reaction mixture was transferred to a dialysis bag with a molecular weight cutoff of 3500 for purification. After freeze-drying, the desired product was obtained as a tan solid (170 mg). The yield was 89.5%.

[0111] The structural characterization data are as follows:

[0112] Hydrogen spectrum: 1 H NMR (500 MHz, D2O)

[0113] PDTTBS: δ (ppm): 3.52-3.03 (br, 4H), 2.64-1.51 (br, 12H)

[0114] PDTTPS: δ (ppm): 3.95-2.92 (br, 4H), 2.65-0.86 (br, 16H)

[0115] PDTTHS: δ (ppm): 3.71-2.83 (br, 4H), 2.65-0.70 (br, 20H)

[0116] Molecular weight: GPC: PDTTBS: Mn = 65.5 Kda, Mw = 68.6 KDa, PDI = 1.046

[0117] PDTTPS: Mn = 88.2 Kda, Mw = 91.9 KDa, PDI = 1.043

[0118] PDTTHS: Mn = 113.7 Kda, Mw = 114.2 KDa, PDI = 1.004.

[0119] Example 2, Spectral properties of polymers PDTTBS, PDTTPS and PDTTHS

[0120] Figure 2 UV-Vis absorption spectra of polymer PDTTBS, PDTTPS and PDTTHS thin films.

[0121] From the above figures, it can be seen that the optical band gap of PDTTBS is 2.25 eV, and the optical band gaps of PDTTPS and PDTTHS are both 2.27 eV. Figure 2

[0122] Example 3, Electrochemical properties of polymers PDTTBS, PDTTPS and PDTTHS

[0123] Figure 3 Cyclic voltammograms of polymer PDTTBS, PDTTPS and PDTTHS.

[0124] ​The electrochemical properties of the polymers were measured using cyclic voltammetry. Polymer films were deposited onto a glassy carbon electrode using the drop-film method. A conventional three-electrode system was employed, with a platinum electrode as the counter electrode, a glassy carbon electrode as the working electrode, a silver / silver chloride electrode as the reference electrode, and a solution of tetrabutylammonium hexafluorophosphate in anhydrous acetonitrile as the supporting electrolyte. The scan range was -2 to 2 volts (vs. silver / silver chloride).

[0125] from Figure 3 It can be seen that the initial oxidation peak potentials of polymers PDTTBS, PDTTPS and PDTTHS are 1.01, 0.93 and 0.98 V, from which their HOMO energy levels are estimated to be -5.41, -5.33 and -5.38 electron volts, respectively.

[0126] Figure 4 The potential difference generated across the polymer PDTTBS at different humidity levels (70%, 80% and 90%) when a temperature difference of 0.61K is applied.

[0127] A PDTTBS sample was prepared by spin-coating 20 μL of a 40 mg / mL PDTTBS aqueous solution onto a 1 cm x 1 cm glass slide containing parallel platinum electrodes 0.5 mm apart and 5 mm long. The sample was then placed across a Peltier module (which can stably generate a 0.61 Kelvin temperature difference), and the potential difference across the material was measured after applying the temperature difference.

[0128] Figure 5 The potential difference generated across the polymer PDTTPS at different humidity levels (70%, 80% and 90%) when a temperature difference of 0.61K is applied.

[0129] A PDTTPS sample was prepared by spin-coating 20 μL of a 40 mg / mL PDTTPS aqueous solution onto a 1 cm x 1 cm glass slide containing parallel platinum electrodes 0.5 mm apart and 5 mm long. The sample was then placed across a Peltier module (capable of stably generating a 0.61 Kelvin temperature difference) and the potential difference across the material was measured after applying the temperature difference.

[0130] Figure 6 The potential difference generated across the polymer PDTTHS at different humidity levels (70%, 80% and 90%) when a temperature difference of 0.61K is applied.

[0131] A PDTTHS sample was prepared by spin-coating 20 μL of a 40 mg / mL aqueous solution of PDTTHS onto a 1 cm x 1 cm glass slide containing parallel platinum electrodes 0.5 mm apart and 5 mm long. The sample was then placed across a Peltier module (which can stably generate a 0.61 Kelvin temperature difference), and the potential difference across the material was measured after applying the temperature difference.

[0132] Figure 7 Graph showing the performance parameters of conductivity, ion Seebeck and power factor of the polymers PDTTBS, PDTTPS and PDTTHS of the present invention at 70%, 80% and 90% humidity.

[0133] By measuring the conductivity and ionic Seebeck of polymers PDTTBS, PDTTPS and PDTTHS at different humidity, the power factors of polymers PDTTBS, PDTTPS and PDTTHS were calculated using the formula.

[0134] Power Factor = Ion Seebeck 2 ×Conductance

[0135] Depend on Figure 7 It can be seen that the three polymers PDTTBS, PDTTPS and PDTTHS synthesized in the present invention have good ionic thermoelectric properties and have good application prospects in the field of ionic thermoelectric materials.

[0136] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that further improvements can be made to the present invention. In short, according to the principles of the present invention, this application is intended to include any changes, uses or improvements to the present invention, including changes that depart from the disclosed scope in this application and are made using conventional techniques known in the art.

Claims

1. Polymer represented by formula I: In formula I, m is an integer between 4 and 10; n is 5 to 500.

2. The polymer according to claim 1, characterized in that: In the formula I, m is 4-6; n is 50-300.

3. A method for preparing the polymer of formula I according to claim 1 or 2, comprising the steps of: In the presence of an oxidizing-reducing agent, the compound represented by formula V is polymerized in a sulfuric acid aqueous solution to obtain a polymer represented by formula I. In the formula V, the definition of m is the same as the definition of m in the formula I in claim 1.

4. The method according to claim 3, wherein: The oxidation-reduction agent is ferrous sulfate heptahydrate-sodium persulfate; The molar ratios of the compound represented by formula V, ferrous sulfate heptahydrate and sodium persulfate are 1.0:0.55-0.65:1.95-2.05 respectively.

5. The method according to claim 3 or 4, characterized in that: The polymerization reaction temperature is 15 to 35° C. The polymerization reaction time is 12 to 48 hours; The polymerization reaction is carried out under an inert atmosphere; The sulfuric acid aqueous solution is a 1 mol / L sulfuric acid aqueous solution.

6. A method for preparing the compound of formula V according to claim 3, comprising the steps of: (1) 4-methoxyphenol reacts with the dibromoalkane represented by Formula 1 in a potassium carbonate solution to obtain a compound represented by Formula II; In Formula 1 and Formula II, m is an integer between 4 and 10; (2) reacting the compound of formula II obtained in step 1) with magnesium chips, zinc bromide, 3,5-dibromo-dithieno[3,2-b:2′,3′-d]thiophene and a palladium catalyst in three consecutive steps to obtain a compound of formula III; In formula III, m is an integer between 4 and 10; (3) reacting the compound represented by formula III obtained in step 2) with boron tribromide to obtain the compound represented by formula IV after completion of the reaction; In the above formula IV, m is an integer between 4 and 10; (4) reacting the compound represented by Formula IV obtained in step 3) with sodium sulfite in a mixed solvent of water and ethanol to obtain a compound represented by Formula V after completion of the reaction; 7. The following compounds: In Formula III, Formula IV, and Formula V, m is an integer within the range of 4-10.

8. Use of the polymer represented by formula I according to claim 1 or 2 as an organic ionic thermoelectric material.

9. Use of the polymer represented by formula I according to claim 1 or 2 in the preparation of organic ionic thermoelectric materials.

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