A method for separating optical isomers of single-walled carbon nanotubes

Abstract

The application provides a method for separating optical isomers of single-walled carbon nanotubes. The method comprises: mixing a single-walled carbon nanotube raw material, a conjugated polymer and an organic medium to form a mixed system, wherein the organic medium comprises a chiral organic component; performing dispersion treatment on the mixed system to make the conjugated polymer selectively wrap and disperse target chiral and optical configuration single-walled carbon nanotubes under the participation of the organic component, and form a dispersion system; and performing post-treatment on the dispersion system. By adding the chiral organic component, the chiral recognition process and the polymer wrapping process are simultaneously performed, the different optical isomers of the carbon nanotubes can be differentially selected, higher-level fine separation is realized, the separation from chiral species is further improved to the separation of optical isomers, and the intrinsic structure and excellent optical performance of the carbon nanotubes can be well maintained without covalent modification of the carbon nanotubes.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a method for separating optical isomers of single-walled carbon nanotubes. Background Technology

[0002] The separation of optical isomers of single-walled carbon nanotubes (SHU) is a higher-level technical problem than traditional single-chirality separation in the field of fine separation of SHU structures. SHU are typically characterized by their chirality index (n, m), with different chirality indices determining their diameter, helix angle, band structure, and optical transition characteristics. Most existing separation techniques aim to obtain SHU with a specific chirality, such as separating (6,5), (7,5), (8,6), or (10,5) single-chirality SHUs. However, for SHU with the same chirality index, there exists a pair of mirror-image optical isomers, i.e., structural units with opposite helical configurations or opposite optical responses. Therefore, the traditional concept of "single-chirality carbon nanotube separation" is not equivalent to "optical isomer separation." The former mainly addresses the separation between different (n, m) structures, while the latter further requires the identification, enrichment, or separation of left- and right-handed helical configurations within the same (n, m) structure.

[0003] Optical isomers of single-walled carbon nanotubes (SHUs) hold significant application potential in chiral optics, circularly polarized light emission, circularly polarized light detection, chiral quantum light sources, asymmetric photoelectric response devices, and biological chiral recognition. However, obtaining SHUs with only a single chiral index is insufficient to fully satisfy the requirements for controllable material structure. If two isomers with opposite optical configurations exist simultaneously within a sample with the same chiral index, their circular dichroism response, circularly polarized light emission asymmetry factor, and chiral photoelectric response may cancel each other out or be significantly weakened, thereby reducing the material's performance in chiral optoelectronic devices. Therefore, achieving selective separation of optical isomers of SHUs beyond single chiral index separation is a key technological direction for improving the structural purity, optical activity, and device consistency of carbon nanotubes.

[0004] Currently, the separation of optical isomers of single-walled carbon nanotubes (SHU) remains in a relatively limited developmental stage. Existing methods such as density gradient ultracentrifugation, gel chromatography, aqueous two-phase extraction, DNA-assisted separation, surfactant-selective dispersion, and selective encapsulation with conjugated polymers in organic phases primarily rely on differences in diameter, electron type, chirality index, surface adsorption behavior, solvation state, or polymer encapsulation stability to separate SHU with different (n,m) structures. For optical isomers that are mirror images of each other within the same chirality index, the aforementioned methods typically cannot directly provide sufficient optical configuration recognition capabilities due to their highly similar diameters, electronic structures, and conventional spectral characteristics. Therefore, while existing separation methods can obtain SHU carbon nanotubes with a certain purity, they still fall short in further distinguishing and enriching different optical isomers within the same (n,m) structure.

[0005] Among these methods, the selective encapsulation of organic-phase conjugated polymers offers advantages such as relatively simple procedures, stable dispersion systems, and good compatibility with organic optoelectronic device fabrication processes, making it an important method for enriching single-walled carbon nanotubes with chirality. However, conventional conjugated polymer systems primarily rely on the matching effect between the polymer chain conformation and the carbon nanotube surface structure. Their recognition targets are typically carbon nanotubes with different chiral indices, rather than left- or right-handed configurations within the same chiral index. Therefore, to further apply this type of method to the separation of optical isomers of single-walled carbon nanotubes, it is necessary to introduce components that provide chiral recognition into the existing polymer selective encapsulation system. This transforms the separation interface from a typical polymer-carbon nanotube interaction interface into a chiral recognition interface with optical configuration selectivity.

[0006] Existing technologies also include methods for regulating the encapsulation behavior of conjugated polymers through second solvents, small molecule additives, or molecular chaperones. These methods typically improve the separation purity and yield of carbon nanotubes with specific chiral indices by altering the system's solvent environment, polymer chain conformation, complex stability, or sedimentation behavior. For example, adding alcohols, ketones, or nitriles as second solvents can change the dissolution and sedimentation equilibrium of polymer-carbon nanotube complexes; adding small molecule chaperones can regulate the folding and adsorption behavior of conjugated polymers on the carbon nanotube surface. While these methods can improve the separation of single-chiral-index carbon nanotubes, their primary purpose remains to enhance the enrichment efficiency of specific (n,m) structures, without establishing a chiral recognition mechanism for optical isomers within the separation system.

[0007] For optical isomers of single-walled carbon nanotubes, simply adjusting solvent ratios, polymer concentrations, ultrasonic conditions, centrifugation conditions, or sedimentation methods is usually insufficient to fundamentally achieve left- or right-handed configuration selection. This is because these process parameters primarily affect the degree of carbon nanotube unbundling, dispersion stability, and polymer encapsulation efficiency, while the differences between two optical isomers with the same chiral index are minimal depending on these conventional separation factors. If the separation system lacks a recognition unit with a clearly defined chiral configuration, the polymer encapsulation process cannot produce stable and controllable selectivity differences between two mirror-image optical isomers.

[0008] Therefore, to achieve effective separation of optical isomers of single-walled carbon nanotubes, it is necessary to introduce a chiral organic component into the conjugated polymer separation system. This chiral organic component possesses a defined R / S configuration, axial chiral structure, or other chiral structure, and can participate in the processes of carbon nanotube dispersion, polymer encapsulation, and polymer-carbon nanotube composite interface formation. Through π-π interactions, hydrogen bonding, dipole interactions, steric hindrance effects, or other non-covalent interactions, the chiral organic component can regulate the arrangement and encapsulation configuration of the conjugated polymer on the carbon nanotube surface, and introduce a chiral recognition environment into the composite interface. Thus, a synergistic effect can be formed between the polymer, the chiral organic component, and the single-walled carbon nanotubes, enabling the system not only to selectively enrich carbon nanotubes with the target chiral index, but also to further differentiate the optical configurations within the same chiral index.

[0009] Therefore, current technologies still lack a method for selectively enriching the optical isomers of single-walled carbon nanotubes in conjugated polymer separation systems. In particular, how to achieve detectable differential enrichment of different optical configurations within single-walled carbon nanotubes of the same chirality index in a simple, mild manner compatible with existing polymer separation processes, without covalently modifying the single-walled carbon nanotubes or significantly damaging their intrinsic structure and optical properties, remains a pressing technical problem to be solved in this field. Based on this, it is necessary to provide a method for separating the optical isomers of single-walled carbon nanotubes by introducing chiral organic components into a conjugated polymer separation system, thereby further improving upon traditional single-chirality index separation to achieve selective enrichment of optical isomers. Summary of the Invention

[0010] The main objective of this invention is to provide a method for separating optical isomers of single-walled carbon nanotubes, so as to overcome the shortcomings of the prior art.

[0011] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0012] This invention provides a method for separating organic systems of optical isomers of single-walled carbon nanotubes, comprising:

[0013] A mixed system is formed by mixing single-walled carbon nanotube raw material, conjugated polymer and organic medium, wherein the organic medium contains chiral organic components;

[0014] The mixed system is dispersed to allow the conjugated polymer, with the participation of the chiral organic component, to selectively encapsulate and disperse the target chiral and optically active single-walled carbon nanotubes, thus forming a dispersion system.

[0015] The dispersion system was separated to obtain a product enriched with target chiral and optically active single-walled carbon nanotubes;

[0016] The chiral organic component is a chiral organic molecule with a chiral center and / or axial chiral structure, which can form non-covalent interactions with the conjugated polymer and / or single-walled carbon nanotubes. It is used to participate in the construction of the polymer encapsulation interface and enhance the differential recognition of the target optically active single-walled carbon nanotubes.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0018] The separation method provided by this invention introduces chiral organic components before dispersion treatment, enabling the optical isomer recognition process to proceed simultaneously with the polymer encapsulation process. Building upon existing methods for separating monochiral single-walled carbon nanotubes using polymers, this method allows for differential selection of different optical isomers of carbon nanotubes, achieving a higher level of fine separation: from chiral type separation to optical isomer separation. This technical solution uses non-covalent interactions to achieve optical isomer separation, eliminating the need for covalent modification of the carbon nanotubes, thus better preserving the intrinsic structure and excellent optical properties of the carbon nanotubes.

[0019] Among them, there is a significant synergistic effect between polymers and chiral organic components. The former is responsible for the initial enrichment of monochiral species, while the latter is responsible for the further differentiation of optical isomers, thus forming a complete and effective fine separation technology route.

[0020] Furthermore, the separation method provided by this invention allows the chiral recognition process to be carried out simultaneously with the polymer separation process, avoiding complex post-processing steps, and is simple and easy to operate.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is the ultraviolet-visible-near-infrared absorption spectrum of the single-walled carbon nanotube raw material used in Example 1 of this invention;

[0024] Figure 2 This is a circular dichroism chromatogram of the separated single-walled carbon nanotube dispersion provided in Example 1 of the present invention;

[0025] Figure 3 These are the absorption spectra of the separated single-walled carbon nanotube dispersions provided in Example 1 and Comparative Example 1 of this invention.

[0026] Figure 4 This is a circular dichroism chromatogram of the separated single-walled carbon nanotube dispersion provided in Comparative Example 2 of this invention.

[0027] Figure 5 This is a circular dichroism chromatogram of the separated single-walled carbon nanotube dispersion provided in Example 2 of the present invention;

[0028] Figure 6 This is a circular dichroism chromatogram of the separated single-walled carbon nanotube dispersion provided in Example 3 of the present invention;

[0029] Figure 7 This is a circular dichroism chromatogram of the separated single-walled carbon nanotube dispersion provided in Example 4 of the present invention;

[0030] Figure 8 This is a circular dichroism chromatogram of the separated single-walled carbon nanotube dispersion provided in Example 5 of the present invention. Detailed Implementation

[0031] While existing polymer selective separation techniques can enrich single-walled carbon nanotubes of chiral types such as (6,5), (7,5), and (10,5), and improve separation efficiency and selectivity through "molecular chaperones," i.e. small molecule additives, the resulting samples usually still contain two optical isomers of the same chiral type, thus not yet achieving a higher level of chiral fine separation.

[0032] Polymers are mainly used as chiral-sensitive selective encapsulation and dispersion media. Their ability to distinguish optical isomers is limited, making it difficult to further break the coexistence of two enantiomers within the same chiral carbon nanotube. The molecular chaperones used only play a role in promoting encapsulation kinetics and cannot distinguish optical configurations.

[0033] Therefore, existing methods lack a simple, mild, and conventional polymer separation process to identify and selectively enrich carbon nanotube optical isomers without damaging the intrinsic structure of carbon nanotubes or introducing complex covalent modifications.

[0034] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0036] To address the aforementioned problems, the present invention aims to provide a novel method for separating organic systems containing optical isomers of single-walled carbon nanotubes. This method is based on the selective separation of single-walled carbon nanotubes using polymers such as PFO, PFO-BPy, and F8BT. R / S-type chiral organic components are added to the liquid-phase system, allowing these chiral organic components to participate simultaneously in system construction during polymer encapsulation and carbon nanotube dispersion. This enhances the system's ability to differentiate between different optical isomers of the same chiral carbon nanotube, enabling further separation or selective enrichment.

[0037] Based on the above technical concept, this invention proposes a novel method for introducing a chiral organic component with chiral recognition capability into a conjugated polymer dispersion system. This chiral organic component can regulate the spatial conformation and folding dynamics of the conjugated polymer at the molecular scale, promoting its ordered encapsulation on the surface of SWCNTs with the target chirality and selected optical rotation configuration, thereby significantly improving the matching efficiency between the polymer and carbon nanotubes.

[0038] As the core technical solution proposed in this invention, embodiments of this invention provide a method for separating organic systems of optical isomers of single-walled carbon nanotubes, comprising the following steps:

[0039] A mixed system is formed by mixing single-walled carbon nanotube raw material, conjugated polymer and organic medium, wherein the organic medium contains chiral organic components;

[0040] The mixed system is dispersed to allow the conjugated polymer, with the participation of the chiral organic component, to selectively encapsulate and disperse the target chiral and optically active single-walled carbon nanotubes, thus forming a dispersion system.

[0041] The dispersion system was separated to obtain a product enriched with target chiral and optically active single-walled carbon nanotubes;

[0042] The chiral organic component is a chiral organic molecule with a chiral center and / or axial chiral structure, which can form non-covalent interactions with the conjugated polymer and / or single-walled carbon nanotubes. It is used to participate in the construction of the polymer encapsulation interface and enhance the differential recognition of the target optically active single-walled carbon nanotubes.

[0043] The above technical solution provides a method for improving the separation purity and selectivity of single-chiral single-walled carbon nanotubes by adding chiral organic components to a conjugated polymer dispersion system. This method utilizes small-molecule chiral organic components (also known as "molecular chaperones") to regulate the conformation and encapsulation kinetics of the conjugated polymer in the organic phase system, enabling the polymer to more efficiently and directionally adsorb and disperse target chiral and optically active carbon nanotubes, thereby significantly improving the separation yield while maintaining high purity.

[0044] In the above method, chiral organic components are directly introduced into the dispersion system of polymer-separated single-walled carbon nanotubes, so that the chiral organic components participate in the system construction in the initial stage of polymer encapsulation and carbon nanotube separation, thereby achieving further separation of the optical isomers of carbon nanotubes.

[0045] It should be noted that, in addition to having a chiral structure or a selected optical configuration, the chiral organic component in this invention should also be able to form a mixed system suitable for dispersion treatment together with the conjugated polymer, single-walled carbon nanotube raw material, and organic medium. The chiral organic component is added to the system before and / or during the dispersion treatment, so that it exists concurrently with the unbundling of single-walled carbon nanotubes, encapsulation by the conjugated polymer, and subsequent separation treatment, rather than being added as a simple detection reagent after separation.

[0046] Under the same separation conditions, the resulting dispersions of single-walled carbon nanotubes with the target chiral index exhibited different optical rotation responses in chiral optical characterization, such as circular dichroism spectroscopy. These results indicate that the introduction of chiral organic components enables the conjugated polymer separation system to produce differential enrichment effects on single-walled carbon nanotubes with different optical rotation configurations of the same chiral index, thereby achieving selective enrichment of single-walled carbon nanotubes with the target chiral index and target optical rotation configuration.

[0047] Therefore, the key to solving the problem of deep separation of single-chiral selected optical configuration is that the selected chiral organic component must not only belong to the "molecular chaperone" mentioned in the prior art, but also have chiral characteristics, and its optical configuration can be artificially selected, thereby exerting optical selectivity in the kinetic behavior of the conjugated polymer.

[0048] In a typical embodiment, after treatment with R-configuration and S-configuration chiral organic components respectively, the resulting samples exhibit circular dichroism signals with opposite signs, thus proving that the method can achieve differential selection and effective characterization of optical isomers of carbon nanotubes. At the same time, the same results can be obtained by using optical rotation testing, polarization spectroscopy or other chiral optical characterization methods as supplementary verification means, which will not be elaborated further in this invention.

[0049] For the chiral organic components that play a key role in this invention, distinguished by chiral configuration, in some embodiments, the chiral organic components are organic molecules having R / S enantiomers, having central chirality, axial chirality, planar chirality, and / or helical chirality.

[0050] Depending on the specific compound type, in some embodiments, the chiral organic component includes chiral aromatic amine compounds, preferably R / S-phenylethylamine, R / S-naphthylethylamine, R / S-bromophenylethylamine, R / S-chlorophenylethylamine, etc.; chiral aromatic alcohol compounds, preferably R / S-phenylethanol, R / S-1-phenylethanol, R / S-naphthylethanol, etc.; chiral binaphthol compounds, preferably R / S-binaphthol, R / S-dibromobinaphthol; and chiral diamine compounds, preferably R / S-diphenylethylenediamine, R / S-, cyclohexanediamine, etc., chiral amino alcohols, preferably R / S-phenylglycine, R / S-phenylalanine, etc., chiral amino acid compounds, preferably R / S-phenylalanine, R / S-tyrosine, R / S-tryptophan, etc., chiral tartaric acid derivatives, and any one or more of the derivatives of the above-mentioned compounds; when the chiral organic component is a combination of multiple compounds, the chiral configurations of the multiple chiral organic components are the same.

[0051] In some embodiments, among the different types of compounds mentioned above, the chiral organic component is preferably a chiral organic molecule with an aromatic π-conjugated system. The chiral organic molecule has a strong non-covalent interaction with the conjugated polymer, which theoretically has a more efficient separation efficiency.

[0052] As a specific example of an optional chiral organic component, the chiral organic component includes, but is not limited to, any one or more combinations of R / S-phenylethylamine, R / S-naphthylethylamine, R / S-bromophenylethylamine, R / S-1,1′-bi-2-naphthol, R / S-octahydro-1,1′-bi-2-naphthol, R / S-2,2′-diamino-1,1′-binaphthol, R / S-2,2′-bis(diphenylphosphino)-1,1′-binaphthol, and derivatives of these compounds. Furthermore, when the chiral organic component is selected from a combination of multiple compounds, the chiral configuration of the multiple chiral organic components remains consistent.

[0053] In addition to the examples above, other chiral organic components with R / S enantiomers that can form differential non-covalent interactions with polymers and carbon nanotubes can also be used as alternatives.

[0054] Regarding the range of compounds for which the applicable conjugated polymers and chiral organic components can be selected, in some embodiments, the conjugated polymers are conjugated polymers having a π-conjugated structure.

[0055] Specifically, the conjugated polymer may include any one or a combination of two or more of PFO and its derivatives, PFO-BPy and its derivatives, F8BT and its derivatives, P3HT and its derivatives, and PFIID and its derivatives. In addition to polymers such as PFO, PFO-BPy, and F8BT, other conjugated polymers capable of selectively encapsulating and dispersing the target single-walled carbon nanotubes in organic solvents may also be used, as long as they can synergistically achieve further separation of optical isomers with the chiral organic component; these are all alternative solutions of the present invention.

[0056] Regarding the construction of the mixed system, the present invention provides two methods: one is to use the chiral organic component directly as a dispersant without adding an organic solvent, and the other is to add an organic solvent, in which multiple components are dissolved / dispersed together in the organic solvent. That is, in some embodiments, the chiral organic component is added as an additive to the organic solvent to obtain the organic medium, or in some embodiments, the chiral organic component is used directly as the organic medium.

[0057] In some embodiments, the organic solvent includes any one or a combination of two or more of aromatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, esters, ethers, and nitriles.

[0058] As an example, in some embodiments, the organic solvent may include any one or a combination of two or more of toluene, xylene, chlorobenzene, o-dichlorobenzene, chloroform, methanol, ethanol, isopropanol, acetone, and acetonitrile. Furthermore, other organic solvents suitable for dissolving the polymer and maintaining stable dispersion of the carbon nanotubes may also be used. It should be noted that the selection of the organic solvent and conjugated polymer can refer to conventional compounds in the art, or may differ from conventional compounds, as long as they serve the corresponding function, and is not limited to specific limited embodiments.

[0059] In some implementations, the dispersion process includes ultrasonic dispersion, high-speed shear homogenization, high-pressure homogenization, ball milling, microfluidics, or any combination thereof.

[0060] Regarding the specific preparation sequence, in some embodiments, the chiral organic component is added to the mixture before and / or during ultrasonic treatment; the addition methods include: adding it during the conjugated polymer preparation stage, adding it after the conjugated polymer is dissolved and before adding the single-walled carbon nanotube raw material, or adding it after the single-walled carbon nanotubes are initially dispersed and before separation treatment.

[0061] In some implementations, the post-treatment methods after dispersion include centrifugation, settling, cooling, filtration, membrane separation, or any combination thereof.

[0062] While the addition of the chiral organic component is preferably carried out during the polymer preparation stage (first fully dissolving the conjugated polymer, organic solvent, and molecular auxiliaries, and then adding the carbon nanotube raw material), it can also be added after the polymer is completely dissolved and before the carbon nanotubes are added, or after the carbon nanotubes are initially dispersed but before separation is completed. As long as its essence still belongs to the introduction of chiral organic components to participate in the recognition of optical isomers during the separation process, it belongs to the mixed system constructed before the formal dispersion treatment, and should be regarded as an equivalent alternative of the present invention.

[0063] As a typical example, taking a mixed system in which the components are dissolved in an organic solvent as an example, the chiral organic component in the embodiments of the present invention is selected from low molecular weight compounds with aromatic π systems and chiral units, such as R / S naphthylethylamine, R / S bromophenylethylamine, and R / S phenylethylamine, etc., whose electronic structure can be matched with the conjugated polymer. The amounts of chiral organic component and conjugated polymer are controlled within an appropriate range, which can achieve high dispersion efficiency while ensuring high selectivity. At the same time, the separation method provided by the present invention is applicable to a variety of polymers, such as PFO, PFO-BPy, F8BT, P3HT, PFIID and derivatives of these conjugated polymers, and is also applicable to SWCNT samples with different chirality and different sources. By selectively matching the chiral organic component, adjustable separation for multiple chirality can be achieved, which has high versatility and application potential.

[0064] Of course, those skilled in the art will recognize that, based on the principles disclosed in this invention, intermolecular π–π interactions or halogen bond interactions can be generated to reduce the stiffness of the polymer backbone, promote its directional folding and encapsulation on the target chiral SWCNT surface, and the chiral molecular auxiliaries are not limited to the above examples. The above molecular combinations belong to the limited scope of this invention, but not all embodiments.

[0065] Regarding specific condition parameters, in some embodiments, the volume content of the chiral organic component in the mixed system is 0.025-100%.

[0066] In some embodiments, the carbon nanotube raw material has a mass fraction of 0.05-0.5 mg / mL and the conjugated polymer has a mass fraction of 0.075-1 mg / mL in the mixed system.

[0067] In some embodiments, after the centrifugation process, the target chiral and optically active carbon nanotubes are in the supernatant.

[0068] As an example, in some typical embodiments, a certain proportion of conjugated polymer and single-walled carbon nanotubes can be placed in an organic solvent, and then a certain amount of chiral organic component can be added. After sonicating with appropriate power for a specific time (15 min–1 h), the mixture is quickly transferred to a centrifuge and centrifuged at a rate of 10,000 g–100,000 g for 20 min–2 h. The supernatant is then collected to obtain a dispersion of single-walled carbon nanotubes with the target chirality.

[0069] The technical solution of the present invention will be further described in detail below through several embodiments. However, the selected embodiments are only used to illustrate the present invention and do not limit the scope of the present invention. Unless otherwise specified, the raw materials, reagents and equipment used in the embodiments of the present invention are all commercially available.

[0070] Example 1

[0071] This embodiment provides a process for separating single-walled carbon nanotubes of a target chirality from a product of mixed chirality, as detailed below.

[0072] 1. Merck's SG65i single-walled carbon nanotubes were selected as the raw material. Their chiral composition was characterized using ultraviolet-visible-near-infrared absorption spectroscopy (UV–Vis–NIR). The characterization results are as follows: Figure 1As shown, the results indicate that it contains single-walled carbon nanotubes with various chiralities, mainly including semiconductor chiral types such as (6,5), (7,5), (7,6), (8,4), and (8,6), and also contains a small amount of metallic single-walled carbon nanotubes.

[0073] 2. Prepare a mixed system by adding the conjugated polymer PFO-BPy (Shenzhen Ruixun Materials Optoelectronic Technology Co., Ltd., CAS No.: 1423043-97-3) to 20 mL of toluene, and simultaneously adding a trace amount of chiral R / S naphthylethylamine, in a volume of 1 mL, followed by the addition of carbon nanotube raw material.

[0074] Furthermore, this step employed R-configuration and S-configuration chiral small molecules to construct two separate systems. Specifically, after adding the conjugated polymer to two portions of toluene, R-type naphthylethylamine and S-type naphthylethylamine were added to the two liquid portions, respectively, at a volume of 1 ml. This was used to compare the effects of different enantiomeric small molecules on the separation results of carbon nanotube optical isomers. In both dispersion systems, the concentration of single-walled carbon nanotubes after addition was 0.05 mg / mL, and the concentration of the conjugated polymer after addition was 0.075 mg / mL.

[0075] 3. Under ultrasonication at a power density of 2 W / mL for 15 min, a selected system was obtained. During the ultrasonication process, the polymer preferentially encapsulated and dispersed the target single-walled carbon nanotubes, thereby enriching the (7,5) chiral single-walled carbon nanotubes. Simultaneously, the chiral small molecules interacted non-covalently with the polymer chains, the surface of the carbon nanotubes, and their surrounding microenvironment, exhibiting different interaction tendencies towards different optical isomers within the same chiral carbon nanotube, thus enhancing the system's ability to differentiate between optical isomers.

[0076] 4. After sonication, the resulting dispersion system is separated and purified. The centrifugal acceleration is controlled at 40,000 g, and after centrifugation for 1 hour, the supernatant is collected. After this step, the obtained sample not only achieves enrichment in (7,5) chiral species, but also further achieves separation or selective enrichment of optical isomers within the same chiral species.

[0077] like Figure 2 As shown, the obtained samples were subjected to circular dichroism spectroscopy. The results showed that when the R-configuration chiral small molecule was used in the system, the obtained samples exhibited a type of circular dichroism response; when the corresponding S-configuration chiral small molecule was used in the system, the obtained samples exhibited a circular dichroism response with opposite signs.

[0078] The above results demonstrate that R / S chiral small molecules exhibit different selectivity for the optical isomers of carbon nanotubes, leading to the enrichment of different enantiomers in the system and consequently resulting in opposite directions of circular dichroism signals. Therefore, the circular dichroism chromatographic results can serve as an important characterization basis for the separation effect of optical isomers in this invention.

[0079] Comparative Example 1

[0080] This comparative example is largely the same as Example 1, except that:

[0081] Without adding any chiral organic components, the mixture was prepared using equal amounts of organic solvent, single-walled carbon nanotubes, and conjugated polymer, and then subjected to the same subsequent processing steps.

[0082] like Figure 3 As shown, the absorption value of the target chiral single-walled carbon nanotube dispersion obtained in Example 1 is significantly stronger than that of the target chiral single-walled carbon nanotube dispersion obtained in Comparative Example 1. This indicates that the chiral organic component not only plays a selective role in optical rotation configuration, but also acts as a "molecular chaperone," affecting the encapsulation state of the conjugated polymer on single-walled carbon nanotubes with different optical rotation isomers.

[0083] Comparative Example 2

[0084] This comparative example is largely the same as Example 1, with the main difference being:

[0085] The chiral organic component is replaced with 1-amino-2-methyl-2-hexene, which is also chiral but does not have an aromatic functional group: H2N-CH(CH3)-CH2-CH2-CH=CH2.

[0086] Because this compound only possesses chirality but lacks the "molecular chaperone" interaction with the conjugated polymer and the promoting effect on kinetic behavior, it does not actually participate in the separation process. Therefore, even if this compound were chiral, it could not separate single-walled carbon nanotubes with different optical configurations, such as... Figure 4 As shown, the relevant spectral test results show no obvious optical rotation signal, and it is impossible to distinguish between the two different optical rotation configurations. This indicates that this comparative example can only obtain a homogeneous mixture of the two configurations, so the optical rotation signals cancel each other out.

[0087] Example 2

[0088] This embodiment provides a separation method that utilizes natural sedimentation for post-processing.

[0089] This embodiment is basically the same as Example 1, except that: the chiral organic component is a chiral aromatic ethylamine compound R / S-1-(4-bromophenyl)ethylamine, the conjugated polymer is PCz, and the organic solvent is chloroform; after ultrasonic treatment, instead of centrifugation, the resulting dispersion system is placed at room temperature for 4-48 hours to allow non-target components to settle preferentially, and then the supernatant is collected to obtain a dispersion enriched with target chiral and optically active single-walled carbon nanotubes.

[0090] like Figure 5 As shown, the circular dichroism chromatogram test showed a distinct (6,5) signal peak, and the chromatographic peaks of the two configurations were in opposite directions. The test results indicate that natural sedimentation can also achieve the enrichment of the target optical isomer, suggesting that the post-processing method after sonication is not limited to centrifugation.

[0091] Example 3

[0092] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0093] Replace all organic solvents with 20 mL of chiral phenylethylamine, without adding any other organic solvents;

[0094] This embodiment uses microfluidic dispersion treatment instead of ultrasonic dispersion treatment.

[0095] Specifically, the conjugated polymer PFO was added to R / S-phenylethylamine to prepare a polymer solution. Then, after thorough stirring, single-walled carbon nanotubes were added to achieve a single-walled carbon nanotube concentration of 0.05 mg / mL and a conjugated polymer concentration of 0.075 mg / mL, with a total system volume of 20 mL. The resulting mixture was magnetically stirred for 30–60 min to ensure thorough wetting of the single-walled carbon nanotubes and the formation of a coarse dispersion.

[0096] Subsequently, the coarse dispersion system was transferred to a microjets homogenizer and subjected to microjets dispersion treatment at 100 MPa pressure, with the treatment cycled 5 times. During the treatment, a circulating cooling method was used to control the system temperature to not exceed 30°C. After the microjets treatment, the resulting dispersion system was centrifuged at 40,000 g for 1 h, and the supernatant was collected to obtain a dispersion enriched with the target chiral index and the target optical rotation configuration of single-walled carbon nanotubes.

[0097] The circular dichroism chromatographic tests of the two dispersions obtained in this embodiment are as follows: Figure 6 As shown, there is a distinct (6,5) signal peak, and the chromatographic peaks of the two configurations are in opposite directions, indicating that this embodiment still achieves effective selective enrichment and separation of optical isomers.

[0098] Example 4

[0099] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0100] In this embodiment, high-pressure homogenization is used instead of ultrasonic dispersion, and the chiral organic component is replaced with R / S-bromophenylethylamine, the conjugated polymer is replaced with PFO, 15 mL of bromophenylethylamine and 5 mL of toluene are used.

[0101] Specifically, PFO was added to a mixed organic medium consisting of R / S-bromophenylethylamine and toluene, with a total volume of 20 mL, of which 15 mL was R / S-bromophenylethylamine and 5 mL was toluene. After stirring until the PFO was fully dissolved, single-walled carbon nanotubes were added to achieve a concentration of 0.05 mg / mL for the single-walled carbon nanotubes and 0.075 mg / mL for the PFO. Stirring was continued for 30–60 min to ensure the single-walled carbon nanotubes were fully wetted in the mixed organic medium, resulting in a coarse dispersion system.

[0102] Subsequently, the obtained coarse dispersion system was transferred to a high-pressure homogenizer for high-pressure homogenization and dispersion treatment. During the high-pressure homogenization process, the treatment pressure was controlled at 50–150 MPa to achieve dispersion of the coarse dispersion system under high-pressure homogenization, and the process was repeated 3–8 times. During the treatment, cooling water or a cryogenic bath was used to control the system temperature, ensuring that the system temperature did not exceed 35°C.

[0103] After high-pressure homogenization, the resulting dispersion was centrifuged at 40,000 g for 1 h. The supernatant was collected after centrifugation to obtain a dispersion enriched with the target chiral index and the target optical rotation configuration of single-walled carbon nanotubes.

[0104] The R-configuration and S-configuration of bromophenylethylamine were treated separately according to the above steps, and the resulting dispersions exhibited different optical rotation responses in circular dichroism spectroscopy. For details, please refer to [link to documentation]. Figure 7 As shown, peaks representing the target chirality and their opposite directions can be observed. This result indicates that differential enrichment of optical isomers of single-walled carbon nanotubes can also be achieved using high-pressure homogeneous dispersion in a mixed organic medium composed of PFO as the conjugated polymer, R / S-bromophenylethylamine, and toluene.

[0105] Example 5

[0106] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0107] The chiral organic component was replaced with R / S-1,1′-bi-2-naphthol, and the polymer was F8BT.

[0108] The circular dichroism chromatogram results of the two dispersions obtained in this embodiment are shown below. Figure 8 As shown, similar to the aforementioned embodiments, obvious target chiral peaks are visible, and the peak directions of different configurations are opposite, which will not be repeated here.

[0109] Example 6

[0110] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0111] The chiral organic component was replaced with R / S-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, and the polymer was PFP-Cl.

[0112] Example 7

[0113] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0114] The chiral organic component was replaced with R / S-1-phenylethanol, and the polymer was PFP.

[0115] Example 8

[0116] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0117] The chiral organic component was replaced with R / S-1,2-diphenylethylenediamine.

[0118] Example 9

[0119] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0120] The chiral organic component was replaced with R / S-phenylglycine.

[0121] Example 10

[0122] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0123] The chiral organic component was replaced with R / S-phenylalanine.

[0124] Example 11

[0125] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0126] The chiral organic component was replaced with R / S-diethyl tartrate.

[0127] The above Examples 6-11 all achieved the additional effect of separating single-walled carbon nanotubes with different optical configurations compared to the case without the addition of chiral organic components or with the addition of non-chiral molecular chaperones. The specific test images are similar to those in Example 1 and will not be repeated here.

[0128] Based on the above embodiments, it is clear that the present invention provides a method for introducing trace amounts of chiral organic components during the selective separation of single-chiral single-walled carbon nanotubes from polymers, thereby achieving the identification, separation, or selective enrichment of optical isomers of single-walled carbon nanotubes. On the basis of chiral selective separation, it can further achieve the selective separation of isomers with different optical configurations.

[0129] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for separating optical isomers of single-walled carbon nanotubes, characterized in that, Includes the following steps: A mixed system is formed by mixing single-walled carbon nanotube raw material, conjugated polymer and organic medium, wherein the organic medium contains chiral organic components; The mixed system is dispersed to allow the conjugated polymer, with the participation of the chiral organic component, to selectively encapsulate and disperse the target chiral and optically active single-walled carbon nanotubes, thus forming a dispersion system. The dispersion system was post-processed to obtain a product enriched with target chiral and optically active single-walled carbon nanotubes; The chiral organic component is a chiral organic molecule having a chiral center and / or axial chiral structure, and capable of forming non-covalent interactions with the conjugated polymer and / or single-walled carbon nanotubes. It participates in the construction of the polymer encapsulation interface and enhances the differential recognition of single-walled carbon nanotubes with target optically active configurations. The chiral organic component includes any one or a combination of two or more of the following: chiral aromatic amines, chiral aromatic alcohols, chiral binaphthalenes, chiral diamines, chiral amino alcohols, chiral amino acids, chiral tartaric acid derivatives, and their derivatives. When the chiral organic component is a combination of multiple compounds, the chiral configurations of the multiple chiral organic components are identical.

2. The separation method according to claim 1, characterized in that, The chiral organic component is added as an additive to an organic solvent to obtain the organic medium.

3. The separation method according to claim 2, characterized in that, The organic solvent includes any one or a combination of two or more of aromatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, esters, ethers, and nitriles.

4. The separation method according to claim 3, characterized in that, The organic solvent includes any one or a combination of two or more of toluene, xylene, chlorobenzene, o-dichlorobenzene, chloroform, methanol, ethanol, isopropanol, acetone, and acetonitrile.

5. The separation method according to claim 1, characterized in that, The chiral organic component is used directly as an organic medium.

6. The separation method according to claim 1, characterized in that, The dispersion processing methods include ultrasonic dispersion, high-speed shear homogenization, high-pressure homogenization, ball milling, microfluidics, or any combination thereof.

7. The separation method according to claim 1, characterized in that, The chiral organic component is added to the mixed system before and / or during the dispersion treatment; The addition methods include: adding it during the conjugated polymer preparation stage, adding it after the conjugated polymer is dissolved and before adding the single-walled carbon nanotube raw material, or adding it after the single-walled carbon nanotubes are initially dispersed and before separation treatment.

8. The separation method according to claim 1, characterized in that, The post-processing methods after dispersion include centrifugal separation, static sedimentation, cooling sedimentation, filtration separation, membrane separation, or any combination thereof.

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