A discontinuous imine cleavable carbazolyl conjugated polymer and applications thereof

Abstract

The application discloses a kind of discontinuous imine breakable carbazole-based conjugated polymer and its application.The polymer is with carbazole conjugated unit as main chain repeat unit, in main chain with the imine breakable connection unit containing-C=N- bond is introduced in discontinuous way, and make at least 1 carbazole conjugated unit between any two imine breakable connection units, and the mole proportion of imine breakable connection unit relative to carbazole conjugated unit does not exceed 90%.The polymer of the application keeps the ability of selective coating and liquid phase directional assembly of carbazole skeleton to semiconductor type carbon nanotube in the first stage, and occurs main chain break in the second stage under acidic condition through imine bond hydrolysis, so that adsorption capacity is reduced and easy to elute.The polymer of the application can be used for selective separation and purification of semiconductor type carbon nanotube, and the construction of array carbon nanotube wafer, network carbon nanotube film or device precursor, which helps to realize low residual post-processing while maintaining high separation capacity.

Description

Technical Field

[0001] This invention relates to the field of conjugated polymers and carbon nanomaterials, and particularly to a discontinuous imine-fragmentable carbazole-based conjugated polymer for the separation of semiconductor carbon nanotubes, and a method for the separation and array construction of semiconductor carbon nanotubes using said polymer. Background Technology

[0002] Single-walled carbon nanotubes (SUVs) are widely considered as candidate channel materials for next-generation electronic devices due to their high carrier mobility, sub-10 nanometer-scale channel potential, and excellent electrical properties. However, SUV samples synthesized by conventional catalytic methods typically contain both semiconducting and metallic forms. Only semiconducting SUVs are suitable for channel applications in field-effect devices. Therefore, selectively separating semiconducting SUVs from mixed samples is a crucial prerequisite for realizing the application of carbon nanotube devices.

[0003] In existing technologies, selective coating with conjugated polymers is a commonly used method for separating semiconducting carbon nanotubes. Among them, carbazole-based conjugated polymers are widely used for the extraction of semiconducting carbon nanotubes and subsequent liquid-phase directional self-assembly array construction due to their strong π-π interaction with the carbon nanotube surface and good selectivity for semiconducting carbon nanotubes. However, after separation and assembly, conventional carbazole-based conjugated polymers are usually difficult to completely remove from the carbon nanotube surface, array interior, or substrate interface due to their strong main chain rigidity and strong adsorption force to the carbon nanotube surface. Residual polymers may cause increased contact resistance, increased interface defects, and increased dispersion of device electrical parameters.

[0004] To address the issue of polymer residue, existing technologies have employed methods such as introducing hydrolyzable bonds into the main chain to construct cleavable conjugated polymers. For example, imine bonds are used as continuous linkages throughout the main chain. Although such polymers can release carbon nanotubes through overall hydrolysis after separation, their continuous imine linkages significantly alter the main chain rigidity, conjugation continuity, and coating conformation, resulting in shortcomings in separation selectivity, dispersion stability, and subsequent liquid-phase assembly capabilities.

[0005] Therefore, how to maintain the original separation and assembly capabilities of carbazole-based conjugated polymers while making the polymers more prone to main chain breakage, decreased adsorption capacity, and residue removal during post-processing is a technical problem to be solved in this field. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the problem that although existing carbazole-based conjugated polymers have good selective coating ability in the carbon nanotube separation stage, they are difficult to remove completely from the carbon nanotube surface and substrate interface in the post-processing stage; at the same time, it overcomes the shortcomings of existing continuous polyimide main chain conjugated polymers in terms of separation selectivity, dispersion stability and liquid phase directional self-assembly ability due to changes in main chain rigidity, conjugation continuity, coating conformation and assembly behavior.

[0007] To address the aforementioned technical problems, the present invention aims to provide a discontinuous imine-severable carbazole-based conjugated polymer for the separation of semiconductor carbon nanotubes and its applications, so as to maintain the selective separation and liquid-phase directional self-assembly capability of semiconductor carbon nanotubes while making the polymer more prone to main chain breakage, decreased adsorption capacity, and residue removal in the post-processing stage.

[0008] To achieve the above objectives, a first aspect of the present invention provides a discontinuous imine-severable carbazole-based conjugated polymer for the separation of semiconductor carbon nanotubes. The polymer has carbazole conjugated units as the main chain repeating units, and the main chain further includes imine-severable linking units. These imine-severable linking units are discontinuously distributed in the main chain and satisfy at least one of the following conditions: (i) at least one carbazole conjugated unit is present between any two adjacent imine-severable linking units; (ii) the imine-severable linking units are ordered or periodically distributed, and at least two carbazole conjugated units are present between any two adjacent imine-severable linking units.

[0009] The molar ratio of the imine breakable linker to the carbazole conjugated unit in the main chain does not exceed 90%; the imine breakable linker contains a hydrolyzable –C=N– bond, and the polymer undergoes main chain breakage under acidic conditions through the hydrolysis of the –C=N– bond.

[0010] In a preferred embodiment, the molar ratio of the imine breakable linker to the carbazole conjugated unit in the main chain is 5% to 90%, preferably 10% to 80%, and more preferably 20% to 60%.

[0011] In a preferred embodiment, the carbazole conjugated unit is selected from one or more of carbazole, N-alkylcarbazole, N-arylcarbazole, 2,7-substituted carbazole, 3,6-substituted carbazole, indobenzocarbazole, and dibenzocarbazole.

[0012] In a preferred embodiment, the carbazole conjugated unit is provided with a substituent, which is selected from one or more of alkyl, alkoxy, aryl, fluorinated substituents or polar side chains.

[0013] In a preferred embodiment, the imine breakable linker has the structural formula –N=CH–Ar–CH=N–, where Ar is an arylene group, and the arylene group is selected from one or more of phenylene, biphenylene, fluorene, or their derivatives.

[0014] In a preferred embodiment, the polymer has a number-average molecular weight of 10 kDa to 150 kDa, preferably 20 kDa to 80 kDa, and a dispersion of 1.2 to 3.0.

[0015] In a preferred embodiment, the imine breakable linker units are statistically randomly distributed in the main chain, and at least one carbazole conjugated unit is retained between some adjacent imine breakable linker units; the main chain contains continuous carbazole conjugated segments without –C=N– bonds, and each continuous carbazole conjugated segment contains no less than two carbazole conjugated units; the imine breakable linker units are distributed between adjacent continuous carbazole conjugated segments.

[0016] A second aspect of the present invention provides a method for separating and arranging semiconductor carbon nanotubes, comprising the following steps:

[0017] S1. A raw material containing semiconductor and metallic carbon nanotubes, and the discontinuous imine-severable carbazole-based conjugated polymer according to any one of claims 1 to 7;

[0018] S2. The raw material and the polymer are mixed in an organic solvent, and then dispersed and ultrasonically treated to allow the polymer to selectively coat the semiconductor carbon nanotubes;

[0019] S3. Centrifuge the system obtained in step S2, collect the supernatant, and obtain a dispersion enriched with the semiconductor carbon nanotubes;

[0020] S4. The dispersion is used for liquid-phase directional self-assembly to form a directional array or network film on a substrate;

[0021] S5. Apply acidic conditions to the oriented array or network film to hydrolyze and break the imine breakable linker, and then use a solvent to wash it off to reduce polymer residue.

[0022] In a preferred embodiment, in step S2, the organic solvent is selected from one or more of toluene, xylene, chlorobenzene, o-dichlorobenzene, and tetrahydrofuran; the concentration of the polymer is 0.02 mg / mL to 2 mg / mL; and the concentration of the carbon nanotube raw material is 0.005 mg / mL to 0.5 mg / mL.

[0023] In a preferred embodiment, in step S3, the centrifugal force for centrifugation is 5000g~30000g, and the centrifugation time is 10min~120min.

[0024] In step S5, the acidic conditions are applied for a period of 0.5 min to 60 min; after applying the acidic conditions, a heat treatment is performed at 150°C to 450°C.

[0025] The embodiments of the present invention have the following advantages: 1. The polymer of this invention uses carbazole conjugated units as the main chain repeating units, thus preserving the continuity of the carbazole backbone in the main chain. Therefore, it can maintain the selective coating ability of semiconductor carbon nanotubes during the separation stage and the interfacial spreading and directional alignment ability in the subsequent liquid-phase directional self-assembly. 2. The polymer of the present invention introduces imine breakable linking units in the main chain in a discontinuous manner, and retains at least one carbazole conjugated unit between any two adjacent imine breakable linking units. The molar ratio of the imine breakable linking unit to the carbazole conjugated unit does not exceed 90%, which effectively avoids the continuous polyimide structure in which the imine unit is the only linking mode of the main chain, thereby maintaining the continuity of the π-conjugated backbone of the main chain; 3. Under acidic conditions, the polymer of this invention hydrolyzes into carbonyl and amino groups via –C=N– bonds, resulting in a decrease in the molecular weight of the main chain, a reduction in π-π adsorption capacity, a conformational change, and an increase in solubility. This hydrolysis can be completed under relatively mild conditions, reducing the risk of damage to the carbon nanotube structure. 4. The polymer of this invention can be used to construct arrayed carbon nanotube wafers, networked carbon nanotube films or device precursors, and through post-processing, the percentage of N 1s atoms in the obtained carbon nanotube samples in XPS testing is less than 0.1 at.%, and the Raman D band intensity does not increase significantly, thus realizing a material platform with both high separation capability and low residue characteristics. Attached Figure Description

[0026] Figure 1 This is a schematic diagram comparing the main chain structure of the discontinuous imine breakable carbazole conjugated polymer provided in the embodiments of the present invention with the existing continuous polyimine main chain structure. Figure 2 A schematic diagram of the synthetic route for the discontinuous imine-severable carbazole-based conjugated polymer provided in an embodiment of the present invention; Figure 3 A flowchart of the selective separation process for semiconductor carbon nanotubes provided in an embodiment of the present invention; Figure 4 This is a process flow diagram of wafer-level low-residue post-processing provided in an embodiment of the present invention; Figure 5 The UV-Vis absorption spectrum time evolution diagram of the discontinuous imine-severable carbazole-based conjugated polymer provided in the embodiments of the present invention under acidic conditions. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely examples and do not constitute a limitation on the scope of protection of the present invention.

[0028] See Figure 1 The discontinuous imine-breakable carbazole-based conjugated polymer provided in this invention uses carbazole conjugated units as the main backbone, and introduces connecting units containing –C=N– imine bonds in a discontinuous manner into the main chain. Figure 1 Unlike existing continuous imine-carbazole polymers (imine:carbazole molar ratio of 1:1, with imine linking units serving as the sole linking mechanism throughout the main chain), the polymer of this invention exhibits a molar ratio of imine linking units to carbazole conjugated units ranging from 0.05:1 to 0.9:1 (i.e., imine linking unit content of 5 mol%-90 mol%). Furthermore, the imine linking units are discontinuously distributed within the main chain, meaning that at least one carbazole conjugated unit is retained between any two adjacent imine linking units, ensuring sufficient continuity of the carbazole conjugated backbone in the main chain. In a preferred embodiment, the main chain contains continuous carbazole conjugated segments without –C=N– bonds, each segment comprising at least two carbazole conjugated units; the imine breakable linking units are distributed between adjacent continuous carbazole conjugated segments. Structurally, the polymer of this invention can be a random copolymer obtained through statistical copolymerization (e.g., Figure 1 (as shown in b), or it can be a periodic copolymer obtained by quantitative copolymerization of pre-designed monomers (such as...). Figure 1 (as shown in c) In both structural forms, the main chain retains a carbazole conjugated segment of substantial length, which enables the polymer to maintain selective coating ability of semiconductor carbon nanotubes during the separation stage. At the same time, in the post-processing stage, the presence of imine linking units that can be hydrolyzed by acid makes it easy for the main chain to break, adsorption capacity to decrease, and residue removal to occur.

[0029] The carbazole conjugated units used in the embodiments of this invention include, but are not limited to, carbazole, N-alkylcarbazole, N-arylcarbazole, 2,7-substituted carbazole, 3,6-substituted carbazole, indolocarbazole, dibenzocarbazole, or combinations thereof. To improve the solubility of the polymer in common organic solvents and the dispersion stability for semiconductor carbon nanotubes, one or more of the following substituents—alkyl, alkoxy, aryl, fluorinated substituents, or polar side chains—are typically introduced at the N-position of the carbazole conjugated unit. In each embodiment of this specification, branched alkyl chains are used as representative R groups for illustration, but those skilled in the art should understand that other substituent types are also applicable. The representative structure of the imine breakable linker is –N=CH–Ar–CH=N–, where Ar is an arylene, including but not limited to phenylene, biphenylene, fluorene, or their derivatives. In embodiments where the carbazole conjugated unit itself serves as the linking end, Ar can be directly provided by an arylene containing a carbazole structure.

[0030] Example 1: Preparation of functional monomers for polymerization

[0031] This embodiment provides a method for preparing the key functional monomers used in the discontinuous imine-severable carbazole-based conjugated polymer of the present invention, such as... Figure 2 As shown. The functional monomers include: carbazole dibromo monomer 1, carbazole dialdehyde monomer 2, carbazole diamine monomer 3, carbazole oligomeric dibromo monomer 4, carbazole oligomeric dialdehyde monomer 5, and carbazole oligomeric diamine monomer 6. The preparation methods of each monomer are all conventional methods in the fields of organic synthesis and conjugated polymer preparation. This embodiment provides a representative synthetic route as an example.

[0032] (1) Preparation of carbazole dibromo monomer 1: Using carbazole with a branched alkyl chain at the N-position (e.g., 9-(2-octyldodecyl)carbazole) as the starting material, a dibromination reaction at the 2,7- or 3,6-position is carried out in solvents such as dichloromethane or N,N-dimethylformamide using N-bromosuccinimide (NBS) at room temperature to 40°C. After purification by column chromatography or recrystallization, carbazole dibromo monomer 1 is obtained. Carbazole dibromo monomer 1 serves as a common precursor for subsequent monomers 2, 3, and 4.

[0033] (2) Preparation of carbazole dialdehyde monomer 2: Carbazole dibromo monomer 1 was dissolved in anhydrous tetrahydrofuran, and n-butyllithium (n-BuLi) was added at -78°C for halide metal exchange. N,N-dimethylformamide (DMF) was then added as a formylation reagent. After the reaction was brought to room temperature, the product was purified by hydrolysis, extraction, and column chromatography to obtain carbazole dialdehyde monomer 2. Carbazole dialdehyde monomer 2 is used to provide a –CHO end group in the main chain, which, after condensation with an amino-containing monomer, forms a –CH=N-imine linkage.

[0034] (3) Preparation of carbazole diamine monomer 3: Carbazole dibromo monomer 1 was subjected to a Buchwald–Hartwig amination reaction, and then reacted with benzophenone imine in the presence of a palladium catalyst (such as Pd2(dba)3), a ligand (such as BINAP), and a strong base (such as sodium tert-butoxide) to obtain a diimine intermediate, which was subsequently hydrolyzed with hydrochloric acid to obtain carbazole diamine monomer 3. The carbazole diamine monomer 3 is used to provide a –NH2 end group in the main chain, which forms a –N=CH-imine linkage after condensation with an aldehyde-containing monomer.

[0035] (4) Preparation of carbazole oligomer dibromo monomer 4: A portion of carbazole dibromo monomer 1 is first coupled with a carbazole borate ester compound (obtained from carbazole dibromo monomer 1 via a Miyaura borylation reaction) under palladium catalysis using Suzuki coupling. Stepwise coupling, end-group controlled coupling, and preparative chromatographic purification methods are employed to obtain oligomer dibromo monomer 4 with a predetermined number of carbazole units or an average number of carbazole units, preferably 2 to 10. In this example, x is taken as 2 as a representative example. In Example 3 of this specification, x can also be independently selected from 2, 3, 5, or 10, corresponding to carbazole oligomer dibromo monomers of different lengths. The carbazole oligomer dibromo monomer 4 serves as a common precursor for subsequent monomers 5 and 6.

[0036] (5) Preparation of carbazole oligomer dialdehyde monomer 5: Carbazole oligomer dibromo monomer 4 was diformylated using the same n-BuLi / DMF method as monomer 2 to obtain carbazole oligomer dialdehyde monomer 5 consisting of x carbazole conjugated units linked together and with –CHO ends at both ends; in this embodiment, x is 2, 5, or 10, corresponding to carbazole oligomer dialdehyde monomers of different lengths. In the carbazole oligomer dialdehyde monomer 5, x carbazole conjugated units are sandwiched between two aldehyde groups. This design allows for a discontinuous distribution of "x carbazole conjugated units spaced apart between imine linking units" in the main chain of the subsequent copolymer.

[0037] (6) Preparation of carbazole oligomer diamine monomer 6: Carbazole oligomer dibromo monomer 4 was diaminated using the same Buchwald-Hartwig ammoniation method as monomer 3 to obtain carbazole oligomer diamine monomer 6 consisting of y carbazole conjugated units linked together with –NH2 at both ends; in this embodiment, y is 2, 5, or 10 (y is an independent integer from 1 to 20, preferably 2 to 10; in Example 3, y and x have the same value). After quantitative 1:1 condensation of the carbazole oligomer diamine monomer 6 and the carbazole oligomer dialdehyde monomer 5, a "–(Cz)" structure can be formed in the main chain. x –CH=N–(Cz) y –N=CH–"Ordered discontinuous structure of periodically repeating units".

[0038] Example 2: Preparation of random discontinuous imine-severable carbazole-based conjugated polymers (imine:carbazole molar ratio ≈ 0.6:1)

[0039] See Figure 2The synthetic path shown in the middle section of this embodiment provides a carbazole-based conjugated polymer in which imine linking units are randomly and discontinuously distributed in the main chain. The molar ratio of imine breakable linking units to carbazole conjugated units in the main chain is approximately 0.6:1 (i.e., imine unit content is approximately 60 mol%), and at least one carbazole conjugated unit is randomly spaced between adjacent imine linking units. This embodiment uses carbazole dialdehyde monomer 2, carbazole oligomer dialdehyde monomer 5, and carbazole oligomer diamine monomer 6 for statistical ternary condensation. The specific steps are as follows:

[0040] Step (1), Feeding. Under a nitrogen atmosphere, 0.60 mmol of carbazole dialdehyde monomer 2, 0.30 mmol of carbazole oligomeric dialdehyde monomer 5 (where x=2, i.e., carbazole dimer dialdehyde monomer), and 0.90 mmol of carbazole oligomeric diamine monomer 6 (where y=2, i.e., carbazole dimer diamine monomer) prepared in Example 1 were added sequentially to a clean and dry reaction flask. The molar ratio of monomers 2, 5, and 6 was monomer 2: monomer 5: monomer 6 = 2:1:3. At this feeding ratio, the total molar number of all aldehyde groups and all amino groups is equal (all 1.80 mmol), which can achieve near-stoichiometric total reaction between amino and aldehyde groups in the condensation reaction and avoid the formation of too many end group defects.

[0041] Step (2), Dissolution. Add anhydrous toluene / anhydrous ethanol mixed solvent (volume ratio 4:1, total volume 20 mL) to the reaction flask, and add a catalytic amount of acid catalyst p-toluenesulfonic acid (p-TsOH, about 0.5 mol% relative to the total amount of monomer amino groups); add about 2 g of 4 Å molecular sieve that has been pre-activated at high temperature as a moisture adsorbent to promote the reversible condensation reaction to move towards a higher degree of polymerization.

[0042] Step (3), condensation reaction. The reaction flask was placed in a 30°C water bath and Schiff base condensation reaction was carried out for 24 h under continuous magnetic stirring. Carbazole dialdehyde monomer 2 and carbazole oligomeric diamine monomer 6 condensed to form a linkage structure containing the segment "(Cz)–CH=N–(Cz)y–N=CH–"; carbazole oligomeric dialdehyde monomer 5 and carbazole oligomeric diamine monomer 6 condensed to form a linkage structure containing the segment "(Cz)x–CH=N–(Cz)y–N=CH–". Since the three monomers participated in the condensation randomly in the reaction system according to statistical probability, the imine linkage units in the resulting polymer backbone were randomly and discontinuously distributed, and at least one carbazole conjugated unit was contained between any two adjacent imine linkage units.

[0043] Step (4), post-processing. After the reaction was completed, the molecular sieve was removed by filtration, and the reaction solution was concentrated to about 5 mL under reduced pressure. Then, it was poured into excess methanol (about 200 mL) to precipitate and obtain a dark polymer powder. The obtained powder was extracted sequentially with methanol, acetone and n-hexane in a Soxhlet extractor for 12 h to remove low molecular weight components and residual catalyst. After extraction, the polymer was dissolved in chloroform and then precipitated with methanol. The obtained solid was filtered and dried under vacuum at 50 °C for 12 h to obtain the target polymer powder of this embodiment, denoted as P-Random-60 (imine content about 60 mol%, randomly distributed).

[0044] The obtained P-Random-60 was characterized, and typical results were as follows: the number-average molecular weight (Mn) measured by gel permeation chromatography (GPC, with THF as the mobile phase and polystyrene as the standard) fell within the preferred range of 20 kDa to 80 kDa, and the dispersity fell within the preferred range of 1.2 to 3.0. In ¹H NMR spectroscopy (¹H NMR, 400 MHz, CDCl3), a characteristic singlet of –CH=N– imine protons was observed near the chemical shift δ≈8.5 ppm, and multiplets of carbazole aromatic ring protons were observed in the range of δ≈8.1 to 7.4 ppm. By the ratio of the imine proton peak integral to the carbazole aromatic ring proton peak integral, the molar ratio of imine linking units to carbazole conjugated units in the actual polymer can be quantitatively estimated, compared with the ratio of imine linking units to carbazole conjugated units. Figure 2 The feed ratios of the synthetic route are basically consistent with the design. In Fourier transform infrared (FTIR) spectroscopy, at 1620 cm⁻¹... - The characteristic absorption peak of the C=N stretching vibration can be observed near the ¹, further confirming the successful introduction of the imine linker unit.

[0045] Example 3: Preparation of periodically discontinuous imine-severable carbazole-based conjugated polymers

[0046] See Figure 2 The synthetic path shown below illustrates that this embodiment provides a carbazole-based conjugated polymer in which the imine linker units are distributed in an ordered and periodic manner in the main chain, wherein the polymer main chain contains "(Cz)". x –CH=N–(Cz) y The repeating unit "-N=CH-" appears periodically, and at least two carbazole conjugated units are present between any two adjacent imine linking units. In this embodiment, a quantitative binary condensation is performed using carbazole oligomeric dialdehyde monomer 5 (where x is independently selected from 2, 3, 5, or 10) and carbazole oligomeric diamine monomer 6 (where y is independently selected from 2, 3, 5, or 10, and has the same x value as monomer 5) at a 1:1 molar ratio. The specific steps are as follows:

[0047] Step (1): Feeding. Under a nitrogen atmosphere, 1.00 mmol of carbazole oligomer dialdehyde monomer 5(x) and 1.00 mmol of carbazole oligomer diamine monomer 6(y) prepared in Example 1 were added to a clean and dry reaction flask, ensuring that the total molar number of aldehyde groups and amino groups were strictly equal to guarantee the formation of a high-degree-of-polymerization periodic copolymer. In this example, the following condensation reactions were independently carried out on four monomer combinations (x=y=2), (x=y=3), (x=y=5), and (x=y=10) to obtain four target polymers with different periodic unit lengths.

[0048] Step (2): Dissolution. Add anhydrous toluene / anhydrous ethanol mixed solvent (volume ratio 4:1, total volume 20 mL), add p-toluenesulfonic acid (about 0.5 mol% relative to the total amount of monomeric amino groups) as a catalyst, and add about 2 g of 4 Å molecular sieve that has been pre-activated at high temperature as a moisture adsorbent.

[0049] Step (3): Condensation reaction. Schiff base condensation reaction was carried out for 24 h with continuous magnetic stirring in a 30°C water bath. Since the aldehyde groups at both ends of monomer 5 and the amino groups at both ends of monomer 6 in this embodiment are located at both ends of the carbazole oligomer, each imine linking unit is necessarily connected to both sides of (Cz) during the condensation reaction. x Or (Cz) y In the oligomer fragment (x=y=2 in this embodiment), the imine linking units in the main chain appear periodically according to the repeating units "(Cz)2–CH=N–(Cz)2–N=CH–", and at least two carbazole conjugated units are contained between any two adjacent imine linking units.

[0050] Step (4): Post-processing. The post-processing process is the same as step (4) in Example 2. The obtained target polymer powder is recorded as follows according to the (x,y) groups: when x=y=2, it is recorded as P-Periodic-50 (imine content is about 50 mol%, calculated according to the number of imines / carbazoles in the periodic unit = 2 / (2+2) = 50.0 mol%); when x=y=3, it is recorded as P-Periodic-33 (imine content is about 33.3 mol%, calculated according to 2 / (3+3) = 33.3 mol%); when x=y=5, it is recorded as P-Periodic-20 (imine content is about 20 mol%, calculated according to 2 / (5+5) = 20.0 mol%); when x=y=10, it is recorded as P-Periodic-10 (imine content is about 10 mol%, calculated according to 2 / (10+10) = 10.0 mol%). The imine contents of the four periodic copolymers are 50, 33.3, 20, and 10 mol%, respectively. By adjusting the lengths x and y of the carbazole oligomers of monomer 5 / 6, the imine content can be continuously, quantitatively, and precisely adjusted within the range of 10-50 mol%, and all are ordered periodic distributions.

[0051] The obtained P-Periodic-50, P-Periodic-33, P-Periodic-20, and P-Periodic-10 were characterized, and the typical results were: Mn fell within the preferred range of 20 kDa to 80 kDa, and the dispersity fell within the preferred range of 1.2 to 3.0. The integral ratio of the imine proton peak to the carbazole aromatic ring proton peak in the ¹H NMR spectrum was compared with that of... Figure 2 The theoretical structure of the synthetic route is basically consistent; 1622 cm⁻¹ in FTIR - The absorption peak intensity of the C=N stretching vibration near ¹ is obvious; compared with P-Random-60 in Example 2, the length of the carbazole oligomeric conjugated segment in the main chain of the P-Periodic series polymer in this example is more uniform, and the position of the main absorption band peak in the UV-Vis absorption spectrum is slightly redshifted, which is consistent with the physical picture that the length of the conjugated segment in the main chain tends to be uniform due to the ordered periodic structure.

[0052] Example 4: Preparation of random discontinuous imine-severable carbazole-based conjugated polymers (imine:carbazole molar ratio ≈ 0.8:1)

[0053] This embodiment provides a random, discontinuous imine-splitter carbazole-based conjugated polymer with a high proportion of imine bonds. This embodiment uses a statistical ternary condensation of carbazole dialdehyde monomer 2, carbazole oligomeric dialdehyde monomer 5, and carbazole diamine monomer 3, with a specific molar ratio of carbazole dialdehyde monomer 2: carbazole oligomeric dialdehyde monomer 5 (x=2): carbazole diamine monomer 3 = 1:1:2. At this ratio, the total molar number of aldehyde and amino groups is equal, and the ratio of the number of –C=N– bonds generated by the condensation reaction to the number of carbazole conjugated units in the main chain is approximately 4:5, or approximately 0.8:1. The resulting target polymer powder is designated P-Random-80. This polymer serves as a boundary example with a high imine bond content to illustrate the effect of increasing the –C=N– bond density on acid-triggered cleavage and residue removal.

[0054] Example 5: Preparation of random discontinuous imine-severable carbazole-based conjugated polymers (imine:carbazole molar ratio ≈ 0.9:1)

[0055] This embodiment provides a random, discontinuous imine-fragmentable carbazole-based conjugated polymer with a high imine bond ratio, illustrating the structural design approach when the –C=N– bond content in the polymer of this invention approaches the upper limit of the protection range. This embodiment employs a statistical ternary condensation using carbazole dialdehyde monomer 2, carbazole oligomeric dialdehyde monomer 5, and carbazole diamine monomer 3, wherein carbazole oligomeric dialdehyde monomer 5 is used to introduce continuous carbazole conjugated segments without –C=N– bonds into the main chain.

[0056] Specifically, under a nitrogen atmosphere, carbazole dialdehyde monomer 2, carbazole oligomeric dialdehyde monomer 5 (where x=2), and carbazole diamine monomer 3 were added to a clean, dry reaction flask. The molar ratio of the additives was carbazole dialdehyde monomer 2: carbazole oligomeric dialdehyde monomer 5: carbazole diamine monomer 3 = 7:2:9. At this additive ratio, the total molar number of aldehyde groups and amino groups were equal, and the ratio of the number of –C=N– bonds generated by the condensation reaction to the number of carbazole conjugated units in the main chain was approximately 18:20, or approximately 0.9:1. The remaining solvent, catalyst, reaction temperature, reaction time, and post-treatment process could be carried out as in Example 2. The resulting target polymer powder was designated P-Random-90.

[0057] This polymer, as a boundary example with high imine bond content, can provide a high density of acid-triggered breakage sites; however, due to its relatively low proportion of continuous carbazole conjugated segments, its selective coating ability and liquid-phase directional assembly ability for semiconductor carbon nanotubes may be lower than those of polymers with moderate imine bond content. Therefore, in a preferred embodiment, the molar ratio of –C=N– bonds to carbazole conjugated units is 20% to 60%.

[0058] Example 6: Real-time UV-Vis absorption spectroscopy characterization of acid-triggered imine bond hydrolysis

[0059] See Figure 5 In this embodiment, the acid-triggered main chain cleavage process of the P-Random-60 polymer prepared in Example 2 was characterized in real time by UV-Vis absorption spectroscopy, which directly verifies the process of imine bond hydrolysis, main chain cleavage, and disappearance of conjugated absorption bands in the polymer of the present invention under weakly acidic conditions.

[0060] Specifically, the P-Random-60 polymer was dissolved in a chloroform / tetrahydrofuran mixed solvent to prepare a homogeneous solution with a concentration of approximately 0.05 mg / mL. A small amount of this solution was added to a quartz cuvette containing a small amount of aqueous acidic system (e.g., trifluoroacetic acid / water or hydrochloric acid / tetrahydrofuran, so that the final pH of the system is approximately 3-4), and the ultraviolet-visible absorption spectrum (wavelength range 300-500 nm) was collected at room temperature.

[0061] See Figure 5 The initial UV-Vis absorption spectrum of the polymer shows a strong absorption band at approximately 420 nm, which corresponds to the π–π band of the extended π-conjugated system formed by imine linking units in the main chain. Transition; 30 s after the addition of acidic reagent, the characteristic absorption band of the polymer at approximately 420 nm had significantly decreased, with absorbance dropping from approximately 0.55 to below approximately 0.07. Simultaneously, characteristic absorption peaks of the carbazole chromophore appeared in the short-wavelength region (300–340 nm), indicating that most imine linking units had undergone hydrolytic breakage within 30 s. After 1 min of acid treatment, the long-wavelength region (>360 nm) absorption band had essentially disappeared, and the UV-Vis absorption spectrum of the polymer morphologically resembled that of carbazole dialdehyde monomer 2. Figure 5 The "polymer monomer (Cz-CHO)" curves tend to be consistent, indicating that after treatment for about 1 minute under acidic conditions, the main chain of the polymer of the present invention has been basically hydrolyzed into low molecular weight monomers or oligomer fragments, and the main chain conjugation has been effectively destroyed.

[0062] The above experimental results show that the polymer of the present invention can undergo main chain cleavage in a very short time (tens of seconds to minutes) under weak acidic conditions without the need for strong oxidants, strong acids or high temperature treatment. This provides a mild, controllable and rapid chemical triggering mechanism for subsequent wafer-level low-residue post-processing, which can effectively reduce the risk of damage to the structure and electrical properties of carbon nanotubes.

[0063] Example 7: Selective Separation and Extraction of Semiconductor Carbon Nanotubes

[0064] See Figure 3 In this embodiment, the P-Random-60 polymer prepared in Example 2 is used to selectively separate and extract the original single-walled carbon nanotube raw material. The specific steps correspond to... Figure 3 Steps 1 to 5 are: raw material mixing (step 1), selective coating (step 2), centrifugal separation (step 3), washing and redispersing (step 4), and high-purity uniform dispersion of semiconductor carbon nanotubes (step 5).

[0065] Step 1: Raw material mixing: The raw single-walled carbon nanotube material (in this example, HiPco is used, but CoMoCAT, flotation catalyst, or other commercially available carbon nanotube materials can also be used) and the P-Random-60 polymer prepared in Example 2 are added to o-dichlorobenzene at concentrations of 0.10 mg / mL and 0.60 mg / mL, respectively, so that the polymer concentration falls within the preferred range of 0.02 mg / mL to 2 mg / mL, and the carbon nanotube concentration falls within the preferred range of 0.005 mg / mL to 0.5 mg / mL. The organic solvent can be selected from one or more of toluene, xylene, chlorobenzene, o-dichlorobenzene, and tetrahydrofuran; in this example, o-dichlorobenzene is used.

[0066] Step 2, Selective Coating: The resulting mixture is first treated with a high-shear disperser at 10,000 r / min for 15 min to fully dissolve the polymer and form a preliminary coating on the carbon nanotube material. Then, the system is placed in an ice-water bath and ultrasonically treated at 500 W for 60 min to selectively coat the carbon nanotube surface with polymer chains. The high-shear time is 5 min–60 min, and the ultrasonic time is 10 min–180 min. During ultrasonication, the system temperature is maintained at no higher than 25℃ to avoid damage to the carbon nanotubes. Because the continuity of the carbazole conjugated backbone in the polymer of this invention is maintained, its π–π selective adsorption capacity for semiconducting carbon nanotubes is comparable to that of traditional carbazole-based conjugated polymers, thus enabling selective coating of semiconducting carbon nanotubes while exhibiting weaker coating capacity for metallic carbon nanotubes.

[0067] Step 3, centrifugation: Transfer the obtained dispersion into a 50 mL centrifuge tube and centrifuge at 20000 g and 4℃ for 60 min using a high-speed refrigerated centrifuge. The centrifugal force is 5000 g to 30000 g and the centrifugation time is 10 min to 120 min. Carefully collect the supernatant, which contains approximately 80% of its volume. The supernatant is enriched with semiconductor carbon nanotubes selectively coated by the polymer. The lower sediment contains metallic carbon nanotubes that are not selectively coated by the polymer and carbonaceous impurities.

[0068] Step 4, Washing / Redispersing: Add approximately 5 times the volume of a poor solvent (such as methanol) to the obtained supernatant to precipitate the polymer-carbon nanotube composite. Collect the precipitate by centrifugation and redisperse it with fresh o-dichlorobenzene to wash away excess free polymer. This washing / redispersing process can be repeated 1-3 times to fully remove excess free polymer. The resulting final dispersion is a high-purity, uniform dispersion of semiconductor-type carbon nanotubes redispersed in the organic phase, which can be directly used for the next step of array carbon nanotube wafer fabrication.

[0069] The collected high-purity dispersions were characterized by UV-Vis-NIR absorption spectroscopy. Typical results were as follows: in S... 11 (approximately 1100~1400 nm) and S 22 (Approximately 600~800 nm) The semiconductor absorption band shows a clear and sharp characteristic absorption peak. 11 The characteristic absorption band of the metallic type (approximately 400–600 nm) is significantly suppressed. Quantitative evaluation based on the absorption peak area ratio shows that the purity of the semiconductor carbon nanotubes can reach approximately 99% or more.

[0070] Example 8: DLSA Construction and Acid-Triggered Low-Residue Post-Treatment of Arrayed Carbon Nanotube Wafers

[0071] This embodiment continues to use the enriched semiconductor carbon nanotube dispersion obtained in Example 7 as raw material, and employs DLSA (Dimension-Limited Self-Alignment) technology to construct arrayed carbon nanotube wafers. The DLSA process achieves unidirectional self-alignment of carbon nanotubes along the substrate by limiting the one-dimensional liquid-liquid-substrate contact line, resulting in a high-density, highly oriented semiconductor carbon nanotube array on the silicon wafer surface. Subsequently, according to... Figure 4 The steps shown involve acid-triggered low-residue post-treatment, and the specific process is as follows:

[0072] Step A, DLSA Array Construction: The enriched dispersion obtained in Example 7 was diluted to a carbon nanotube concentration of approximately 0.02 mg / mL and used as the lower organic phase. An aqueous subphase was spread on a clean 300 mm silicon wafer (with a silicon dioxide layer of approximately 90 nm thickness formed by thermal oxidation). The lower organic phase was injected subsurfaced into the subphase via micro-injection, causing the carbon nanotubes to orient themselves at the two-dimensional liquid-liquid interface formed between the aqueous and organic phases. The substrate was pulled along the subphase interface at a rate of approximately 0.1 mm / min and the subphase temperature was controlled at approximately 25°C to form an array of oriented carbon nanotubes on the silicon wafer surface. The resulting array was characterized by scanning electron microscopy (SEM). The carbon nanotube array density was approximately 80–120 nanotubes / μm, with an average orientation angle deviation of less than ±10°, and the array coverage was uniform. At this point, the polymer remained as a coating layer on the carbon nanotube surface, inside the array, and at the substrate interface.

[0073] Step B, Acid-Triggered Polymer Degradation: The silicon wafer with the arrayed carbon nanotube film is immersed in a dilute hydrochloric acid aqueous solution with a pH of approximately 4 and treated at approximately 40°C for 10 min. The acidic conditions can be selected from a weakly acidic aqueous solution with a pH of 3-5, an organic acid system containing trace amounts of water, or an inorganic or organic acid with a concentration of 0.01 mol / L to 2 mol / L, and the treatment time is 0.5 min to 60 min. Under these acidic conditions, the imine linking units (–C=N–) in the polymer backbone undergo acid-catalyzed protonation and nucleophilic addition to water molecules, subsequently cleaving into the corresponding aldehyde and amino groups. The π-conjugation of the backbone is effectively disrupted, and the polymer molecular weight decreases significantly to low molecular weight fragments. Because the polymer of this invention introduces a sufficient number of imine cleavage sites in a discontinuous manner in the backbone, backbone cleavage can be completed in tens of seconds to several minutes under these acidic treatment conditions.

[0074] Step C, Mild Solvent Rinsing: After acid treatment, the silicon wafer is sequentially immersed and washed with o-dichlorobenzene, tetrahydrofuran, and isopropanol for 30 seconds each, for a total of 3 cycles. The solvent system can be further combined with toluene, tetrahydrofuran, chlorobenzene, o-dichlorobenzene, alcohol solvents, or combinations thereof for elution. The solubility of the hydrolyzed and broken low molecular weight polymer fragments in the solvent increases significantly, and their π–π adsorption capacity with the carbon nanotube surface is greatly reduced, thus being carried away by the rinsing solution; the orientation and arrangement of the arrayed carbon nanotube film remain basically unchanged under these mild rinsing conditions.

[0075] Step D, Mild Heat Treatment and Clean Array: The rinsed silicon wafer is placed in a nitrogen atmosphere and subjected to a mild heat treatment at approximately 150°C to 450°C for 0.5 min to 60 min, preferably at 300°C for 10 min, to further remove any remaining low-molecular-weight fragments and improve the interface for subsequent processes. This mild heat treatment is not the only triggering method for imine bond breakage in this invention, but rather an auxiliary step in the post-processing chain, performed after the main chain has already been acid-triggered to break into low-molecular-weight fragments, providing a light purification. Through steps A to D, a clean array of carbon nanotube wafers is finally obtained, which can be used as a precursor for subsequent field-effect transistor device fabrication.

[0076] Characterization of the silicon wafers after steps A through D revealed the following typical results: In X-ray photoelectron spectroscopy (XPS) testing, the percentage of N 1s atoms decreased to approximately 0.08 at.%, below the low residue threshold of 0.10 at.%, and the N 1s peak height was close to the background level; in the XPS high-resolution C 1s spectrum, the C–N characteristic peak at approximately 285.8 eV and the C=N characteristic peak at approximately 287.5 eV were no longer distinguishable, indicating that the nitrogen-containing conjugated units in the polymer had been effectively removed; in the Raman spectrum, the peak at approximately 1340 cm⁻¹... - ¹ The D-band intensity did not show a significant increase compared to the untreated sample, and the D-band to G-band intensity ratio (ID / IG) remained below 0.05, indicating that no significant defects were introduced into the carbon nanotubes during the acid-triggered post-treatment process. These results are consistent with... Figure 4 The process flow shown is consistent with the design expectations, indicating that the polymer of the present invention can achieve low-residue post-processing of wafer-level arrayed carbon nanotubes while maintaining the front-end separation capability of the carbazole-based conjugated backbone.

[0077] Example 9: Construction of network-type carbon nanotube films and multi-substrate compatibility

[0078] The main difference between this embodiment and Example 8 is that a highly aligned array structure is no longer required. Instead, a random network film is constructed using the semiconductor carbon nanotube dispersion purified by the polymer of this invention, and the process adaptability of the polymer of this invention to various device-compatible substrates is verified. Specifically, after obtaining the enriched semiconductor carbon nanotube dispersion using the same steps as in Example 7, the dispersion is diluted to a carbon nanotube concentration of approximately 0.01 mg / mL. The dispersion is then filtered through vacuum onto the surface of an anodized aluminum porous membrane to form a uniform network carbon nanotube film. Subsequently, the network film is transferred to Si, SiO2 (approximately 90 nm thick), HfO2 (approximately 5 nm thick), sapphire, quartz, and glass substrates using a wet transfer process. Continuous, uniform, and dense network carbon nanotube films can be formed on all of the above substrates. Post-processing is then performed according to steps B-D of Example 8, including acid-triggered hydrolysis, solvent washing, and mild heat treatment. XPS testing of the network films on various substrates showed that the N 1s atomic percentage was less than 0.10 at.%, indicating that the polymer of the present invention can achieve low-residue post-processing on various device-compatible substrates such as Si, SiO2, HfO2, sapphire, quartz, and glass, and can be naturally extended to wafer-level processes.

[0079] Comparative Example 1: Preparation and Application of Conventional Carbazole-based Conjugated Polymers (without Imine Severable Linking Units)

[0080] To highlight the beneficial effects of the polymer of this invention, a conventional carbazole-based conjugated polymer was prepared as a control in Comparative Example 1. Its main chain does not contain any imine breakable linker units; that is, the main chain is formed solely by direct coupling of carbazole conjugated units via C-C bonds. Specifically, carbazole dibromo monomer 1 and the corresponding carbazole diboronate monomer (obtained from carbazole dibromo monomer 1 via Miyaura borylation reaction) were subjected to Suzuki coupling copolymerization at a 1:1 molar ratio. Tetra(triphenylphosphine)palladium Pd(PPh3)4 was used as a catalyst, potassium carbonate aqueous solution as a dehalogenating agent, and toluene / tetrahydrofuran mixed solvent as the reaction medium. The reaction was carried out at 85°C for 48 h. After precipitation-extraction-reprecipitation post-treatment as in step (4) of Example 2, the control polymer was obtained, denoted as P-PCz.

[0081] The HiPco raw single-walled carbon nanotube material was dispersed, ultrasonically extracted, and centrifuged using P-PCz in the same process as in Example 7, and then a DLSA array was constructed according to step A of Example 8. Subsequently, acidic elution and mild heat treatment were performed under the same acidic post-treatment conditions as steps B-D of Example 8. XPS characterization of the treated silicon wafers showed typical results: the N 1s atomic percentage remained as high as approximately 0.85 at.%, significantly higher than the low residue threshold of 0.10 at.%; high-intensity C–N characteristic peaks were clearly observed in the C 1s high-resolution spectrum, indicating that the nitrogen-containing carbazole conjugated units in the P-PCz backbone were difficult to remove completely from the carbon nanotube surface, array interior, and substrate interface during acidic post-treatment. Furthermore, in the field-effect devices subsequently fabricated on the Comparative Example 1 sample, the contact resistance was significantly higher than that of the devices in Example 8, the subthreshold swing was larger, and the consistency between devices was poor. The above results demonstrate that the introduction of the imine breakable linker unit described in this invention is a key technical feature for reducing polymer residue and improving wafer-level device performance.

[0082] Comparative Example 2: Preparation and Application of Continuous Polyimide-type Carbazole-based Conjugated Polymers

[0083] See Figure 1 The continuous imine-carbazole polymer structure shown above. In Comparative Example 2, a continuous polyimine-type carbazole-based conjugated polymer with imine linking units and carbazole conjugated units arranged in a strict 1:1 ratio in the main chain was prepared as a control. In this polymer, the imine linking unit is the only linking mode that runs through the entire main chain. The molar ratio of imine linking unit to carbazole conjugated unit is 100 mol%, which belongs to the existing continuous polyimine main chain.

[0084] Specifically, the carbazole dialdehyde monomer 2 and carbazole diamine monomer 3 prepared in Example 1 were subjected to Schiff base condensation at a molar ratio of 1:1. The catalyst (p-toluenesulfonic acid), solvent (anhydrous toluene / anhydrous ethanol), molecular sieve (4 Å), temperature (30°C) and post-treatment process were the same as in Example 2. The resulting control polymer was designated as P-PolyImine.

[0085] HiPco raw single-walled carbon nanotubes were dispersed, ultrasonically extracted, and centrifuged using P-PolyImine in the same manner as in Example 7, and then DLSA arrays were constructed according to step A of Example 8. Subsequently, acidic elution and mild heat treatment were performed under the same acidic post-treatment conditions as steps B-D of Example 8. Typical results showed that the purity of the semiconductor carbon nanotubes extracted by P-PolyImine was significantly reduced (approximately 90%) compared to the polymer P-Random-60 in Example 2. 11 S 22The weak intensity and large half-width of the characteristic absorption peaks in the absorption band indicate a decrease in the selective coating ability of the semiconductor carbon nanotubes. During the construction of the DLSA array, the array density decreased significantly (approximately 30-50 nanotubes / μm), and the orientation angle deviation was large (approximately ±20°). This phenomenon is consistent with the decreased rigidity of the continuous imine backbone, poor conjugation continuity, and the tendency of the backbone conformation to fold more easily, making it difficult to maintain stable liquid-phase interface orientation. Even after acid-triggered hydrolysis and elution under post-treatment conditions, the percentage of N 1s atoms in the obtained carbon nanotube sample in XPS analysis was still approximately 0.62 at.%, higher than the low residue threshold of 0.10 at.%. Furthermore, the array structure exhibited a certain degree of dispersion and displacement during post-treatment due to the complete breakage of the polymer as the sole backbone linking mechanism, resulting in overall instability. The above results show that the discontinuous distribution design described in this invention, which "maintains the separation and assembly capability of the main carbazole backbone and provides post-removal capability of the local imine units", has significant advantages over the existing continuous polyimide backbone scheme. The two cannot be equivalently substituted in terms of front-end separation, mid-end assembly and low-residue back-end.

[0086] Based on the semiconductor carbon nanotube array samples obtained from Examples 2-5 (polymers of the present invention) and Comparative Examples 1 and 2 (control polymers) under the same separation, assembly, and post-processing conditions, the comprehensive characterization results are summarized in Table 1. As a supplement to the XPS residue analysis, Figure 5 Further molecular-level analysis revealed the main chain conjugation disruption process of the representative polymer P-Random-60 under acidic conditions; the comprehensive characterization results of each sample after separation, assembly, and post-processing are summarized in Table 1.

[0087]

[0088] From Example 6 and Figure 5It can be seen that the discontinuous imine-severable carbazole-based conjugated polymer described in this invention can undergo main chain cleavage within tens of seconds to minutes under acidic conditions. Its main chain conjugated absorption band at approximately 420 nm rapidly disappears and tends towards the absorption characteristics of the monomeric carbazole chromophore, verifying the speed and effectiveness of the acid-triggered main chain cleavage mechanism at the molecular level. The optimal performance is observed when the imine content is moderate (20%-60%, with a post-treatment N content of approximately 0.06-0.08 at.%), achieving low polymer residue while maintaining the separation purity of the semiconductor carbon nanotubes and the DLSA array density. When the imine bond content is too low, there are insufficient acid-triggered cleavage sites, and relatively long carbazole conjugated fragments may still form after hydrolysis; when the imine bond content is too high, the proportion of continuous carbazole conjugated fragments decreases, potentially weakening selective coating ability and liquid-phase directional assembly ability. Comparative Example 1 (conventional PCz, completely devoid of imine units) still exhibited a high N 1s content of 0.85 at.%, significantly higher than the embodiments of the present invention, under the same post-treatment conditions. This indicates that the introduction of the imine breakable linking unit described in the present invention is a key technical feature for reducing polymer residue. Although Comparative Example 2 (main-chain continuous polyimide) reached the limit value (1:1) for the content of imine linking units, since the imine linking unit is the only linking method throughout the main chain, its selective coating ability (purity of about 90%) and DLSA array construction ability (density of about 30~50 nanotubes / μm, orientation deviation of about ±20°) for semiconductor carbon nanotubes were significantly reduced during the separation stage. Furthermore, the N 1s residue after post-treatment (about 0.62 at.%) was still higher than the threshold, indicating that simply exchanging more imine linking units for more breakage sites cannot solve the residue problem, but rather impairs the front-end separation and mid-end assembly capabilities. This invention introduces imine breakable linker units into the main chain in a discontinuous manner, and retains at least one carbazole conjugated unit between any two adjacent imine linker units. While maintaining the selective coating and liquid-phase directional assembly capability of the carbazole conjugated framework onto semiconductor carbon nanotubes, it provides a sufficient number of acid-triggered breakage sites, making it easier for the polymer to be removed from the surface of carbon nanotubes, the array interior, and the substrate interface during the post-processing stage. This achieves both "highly efficient separation at the front end" and "low residue at the back end," demonstrating the core technical effect of this invention.

[0089] It should be understood that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A discontinuous imine-severable carbazole-based conjugated polymer, wherein the polymer has carbazole conjugated units as the main chain repeating units, and the main chain further comprises imine-severable linking units, characterized in that... : The imine breakable linker units are discontinuously distributed in the main chain and satisfy at least one of the following conditions: (i) at least one carbazole conjugated unit is contained between any two adjacent imine breakable linker units; (ii) the imine breakable linker units are ordered or periodically distributed, and at least two carbazole conjugated units are contained between any two adjacent imine breakable linker units. The molar ratio of the imine breakable linker to the carbazole conjugated unit in the main chain does not exceed 90%; the imine breakable linker contains a hydrolyzable –C=N– bond, and the polymer undergoes main chain breakage under acidic conditions through the hydrolysis of the –C=N– bond.

2. The discontinuous imine-severable carbazole-based conjugated polymer according to claim 1, characterized in that, The molar ratio of the imine breakable linker to the carbazole conjugated unit in the main chain is 5% to 90%, preferably 10% to 80%, and more preferably 20% to 60%.

3. The discontinuous imine-severable carbazole-based conjugated polymer according to claim 1, characterized in that, The carbazole conjugated unit is selected from one or more of carbazole, N-alkylcarbazole, N-arylcarbazole, 2,7-substituted carbazole, 3,6-substituted carbazole, indolocarbazole, and dibenzocarbazole.

4. The discontinuous imine-severable carbazole-based conjugated polymer according to claim 1, characterized in that, The carbazole conjugated unit is provided with a substituent, which is selected from one or more of alkyl, alkoxy, aryl, fluorinated substituents or polar side chains.

5. The discontinuous imine-severable carbazole-based conjugated polymer according to claim 1, characterized in that, The imine breakable linker has the structural formula –N=CH–Ar–CH=N–, where Ar is an arylene group, and the arylene group is selected from one or more of phenylene, biphenylene, fluorene or their derivatives.

6. The discontinuous imine-severable carbazole-based conjugated polymer according to claim 1, characterized in that, The polymer has a number-average molecular weight of 10 kDa to 150 kDa, preferably 20 kDa to 80 kDa, and a dispersion of 1.2 to 3.

0.

7. The discontinuous imine-severable carbazole-based conjugated polymer according to claim 1, characterized in that, The imine breakable linker units are statistically randomly distributed in the main chain, and at least one carbazole conjugated unit is retained between some adjacent imine breakable linker units; The main chain contains continuous carbazole conjugated segments that do not contain –C=N– bonds, and each continuous carbazole conjugated segment contains at least two carbazole conjugated units; the imine breakable linker units are distributed between adjacent continuous carbazole conjugated segments.

8. A method for separating and arranging semiconductor carbon nanotubes, characterized in that, Includes the following steps: S1. A raw material containing semiconductor and metallic carbon nanotubes, and the discontinuous imine-severable carbazole-based conjugated polymer according to any one of claims 1 to 7; S2. The raw material and the polymer are mixed in an organic solvent, and then dispersed and ultrasonically treated to allow the polymer to selectively coat the semiconductor carbon nanotubes; S3. Centrifuge the system obtained in step S2, collect the supernatant, and obtain a dispersion enriched with the semiconductor carbon nanotubes; S4. The dispersion is used for liquid-phase directional self-assembly to form a directional array or network film on a substrate; S5. Apply acidic conditions to the oriented array or network film to hydrolyze and break the imine breakable linker, and then use a solvent to wash it off to reduce polymer residue.

9. The method according to claim 8, characterized in that, In step S2, the organic solvent is selected from one or more of toluene, xylene, chlorobenzene, o-dichlorobenzene, and tetrahydrofuran; the concentration of the polymer is 0.02 mg / mL to 2 mg / mL, and the concentration of the carbon nanotube raw material is 0.005 mg / mL to 0.5 mg / mL.

10. The method according to claim 8, characterized in that, In step S3, the centrifugal force for centrifugation is 5000 g to 30000 g, and the centrifugation time is 10 min to 120 min. In step S5, the acidic conditions include an aqueous organic acid system, an aqueous inorganic acid system, and an acidified alcohol / ether / aromatic solvent mixture system; the application time of the acidic conditions is 0.5 min to 60 min; after applying the acidic conditions, a heat post-treatment is performed at 150℃ to 450℃.

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